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* McStas, neutron ray-tracing package
*         Copyright 1997-2010, All rights reserved
*         Risoe National Laboratory, Roskilde, Denmark
*         Institut Laue Langevin, Grenoble, France
* Documentation: CHANGES
* %Identification
* Written by: KN, KL, PEO, EF, PW, EK, JB
* Date: 2012
* Origin: DTU, ILL, Uni Copenhagen, PSI
* Release: McStas 2.1
* Modified by: KN, October 26, 1998 : initial release 1.0
* Modified by: KN, March 31, 1999   : release 1.1
* Modified by: KN, January 31, 2000 : release 1.2
* Modified by: KN, May 18, 2000     : release 1.3
* Modified by: KN, July 28, 2000    : release 1.4
* Modified by: KN, PEO, March 16, 2001: release 1.4.1
* Modified by: PEO, EF, October, 10th, 2001: release 1.5
* Modified by: PW, EF, May 19th 2003: version 1.7
* Modified by: PW, EF, March 4th 2004: version 1.8
* Modified by: PW, EF, November 16th 2005: version 1.9
* Modified by: PW, EF, March 29th 2006: version 1.9.1
* Modified by: PW, EF, December 4th 2006: version 1.10
* Modified by: PW, EF, July 3rd 2007: version 1.11
* Modified by: PW, EF, EK May 8th 2008: version 1.12
* Modified by: PW, EF, EK April 2nd 2009: version 1.12a
* Modified by: PW, EF, EK June/July 2010: version 1.12b
* Modified by: PW May-June 2011: version 1.12c (re-release)
* Modified by: PW November 2012: version 2.0RC1 (pre-release)
* Modified by: PW December 2012: version 2.0RC2 (pre-release)
* Modified by: PW December 2012: version 2.0
* Modified by: PW February-July 2014: version 2.1 (and the 2.1RC1 pre-release)
* This file is part of McStas  version 2.1, released September 2014.
* It gives a 'changes' list from the beginning of the project
Changes in McStas v2.1, September, 2014

 McStas 2.1 is the second release in the 2.x series and fixes various issues with McStas 2.0,
 plus provide important new developments.

 IMPORTANT: Please ensure to use our "migration scripts" for McStas 2.0 and 1.12c if you want
 these to co-exist with 2.1. Also, please read the platform-specific notes below!

 - Thanks to all contributors of components, instruments etc.! This is what Open Source
   and McStas is all about!
 - Thanks to Jonas Stein from Uni Cologne for helping us modernize the TeX documentation!
 - Via NeXus libraries and a new --format=Mantid setting for the mcdisplay tool, we are now
   able to generate NeXus/HDF files that can be read and treated by Mantid! Mcdisplay generates
   a Mantid IDF description for embedding in the NeXus file, including the usual McStas instrument
   geometry. Please read the specific guide for this method, documented in the McStas manual, Chapter 6.
 - Use of STATE_PARAMETERS and POLARIZATION parameters is no longer supported!
   If you have home-grown components using these, you will get this type of error with 
   McStas 2.1:

      Translating instrument definition 'BNL_H8.instr' into C ...
      mcstas -t -o BNL_H8.c BNL_H8.instr
      Compiling simulation BNL_H8.instr
      Arm.comp is using STATE PARAMETERS
      	       mcstas-2.1 does NOT support this keyword. Please remove line 36
      mcstas-2.1: 1 Errors encountered during parse of BNL_H8.instr.
      ** Error exit **

   As the error message suggests, this can be fixed by simply removing/commenting out
   the STATE and POLARISATION parameter lines in the top of the component, i.e.:
   /* STATE PARAMETERS (x,y,z,vx,vy,vz,t,s1,s2,p) */
 - In case of "negative time" propagation we no longer ABSORB these neutrons but rather restore
   the incoming neutron state, leaving it untouched for the following components. This avoids
   various types of shadowing effects, e.g. when placing parallel monitors that are not in a 
   GROUP. This is furhter in preparation for the forthcoming ASSEMBLY keyword which will work
   roughly like an "iterative group" that loops on the ASSEMBLY of components until no furhter
   scattering is achieved, but always scatters first on the component which is closest (in time)
   to the neutron.

 - "Scatter logging": With this release we provide this special ensemble of instrument examples
   - Test_Scatter_log_losses.instr
   - Test_Scatter_log_mvalues.instr
   - Test_Scatter_log_ssw_mcnp.instr
   that together with the (misc cathegory) components
   - Scatter_log_iterator.comp
   - Scatter_log_iterator_stop.comp
   - Scatter_logger.comp
   - Scatter_logger_stop.comp
   provide a powerful post-processing mechanism, mainly for guide systems - that for instance
   can be used to study the non-propagated, i.e. absorbed neutron flux along the guide. For
   more information, a paper by Esben Klinkby et. al. will be available in one of the next 
   issues of Journal of Physics: Conference Series, proceedings of the NOP&D 2013 meeting in
   Ismaning. Slides from Esbens talk are available here:

 - As of this release, McStas is distributed using easy-to-use meta-packages for the Windows
   and Mac OS X systems. (these already existed for the deb and rpm based Linux packages, see
   below) The content of these packages are:

   * Windows:
     - See for details
     - Strawberry Perl (including a gcc compiler)
     - Perl PPD extensions for PDL, PGPLOT and Tk
     - The core mcstas package
     - The mcstas component package, with comps, instruments, datafiles
     - The mcstas Perl tools package with mcgui, mcplot etc.
     - The mcstas manuals package with PDF docs
     - For VRML and X3D viewing of instruments, we recommend Instant Player from
     - ! The mcstas Python tool packages are installed by default, but if you want to 
       make use of our OPTIONAL Python based packages, their dependencies need to be installed
       by hand !
       - Needed dependencies for the Python packages are all available in the Python(x,y)
       	 package available from

   - ! We are only distributing a 32bit package for windows, since we feel the 64-bin gcc on
       windows is not mature - gives problems in a few, specific cases. In any case, the 32-bit
       McStas for windows works perfectly fine on a 64-bit operating system !  

   - ! If you experience strange behavior from perl/mcgui on Windows like
       	    a) ppm shell not being able to install the extra Perl packages
            b) mcgui not being able to run / compile a simulation (all you get is mcrun -- help output)
     	    c) mcgui not being able to access local component files
	  - Solution can be to ensure your user has "full control" to the executables in
	    c:\strawberry\perl\bin (Right-click, Properties, Security, Authenticated users -> Edit)

   * Mac OS X:
     - IMPORTANT: Please ensure to use our "migration scripts" for McStas 2.0 and 1.12c if you want
       these to co-exist with 2.1. They MUST be applied before installing 2.1!
     - See for details
     - A McStas 'app' bundle in /Applications/ - you can uninstall all of McStas 2.1
       by dragging this bundle to the trash bin.
     - Tk perl package for mcgui
     - SciPDL package for mcplot, including the core pgplot package
     - The core mcstas package
     - The mcstas component package, with comps, instruments, datafiles
     - The mcstas Perl tools package with mcgui, mcplot etc.
     - The mcstas manuals package with PDF docs
     - For VRML and X3D viewing of instruments, we recommend Instant Player from
     - ! If you want to use our OPTIONAL Python based packages, select these for installation
       in the Metapackage installer !
       - For the Python mcrun, you need to install PyYAML from
       - Most other needed dependencies for the Python packages are available through the 
       	 SciPy superpack available from
       - You may also choose the commerical Anaconda or Enthought Python distributions
   - ! The install location of the McStas components and libraries on Mac OS X has changed! Your files
       are now placed in /Applications/ - but for ease
       of use, a link is also available in /usr/local/mcstas/2.1/ (Note that we have dropped 'lib' in 
       that path.) Links to binaries are in /usr/local/bin.

   * For Linux (Debian and RPM based)
     - IMPORTANT: Please ensure to use our "migration scripts" for McStas 2.0 and 1.12c if you want
       these to co-exist with 2.1. They MUST be applied before installing 2.1! 
     - See for details
     - For some RPM based systems, you may futher need to install the EPEL extensions, see
     - For Deb and RPM type systems we provide a set of APT and YUM repositories. Simply follow the
       instructions on the link provided to add the relevant repository to your Linux.
     - Afterwards, simply choose to install mcstas-suite-perl (perl tools), mcstas-suite-python 
       (python tools) or mcstas-suite (both toolsets) and all dependencies should be taken care of.

   - ! The install location of the McStas components and libraries on Linux X has changed! 
       * On Debian, your files are now placed in /usr/share/mcstas/2.1/ - links to binaries are in /usr/bin
       * On RedHat, your files are now placed in /usr/local/mcstas/2.1/ - links to binaries are in /usr/local/bin
       (Note that we have dropped 'lib' in the mcstas system path.)

 - A given McStas 2.x release is "self-contained" and can be installed in parallel with other versions
   of McStas and McXtrace 
 - We provide a "migration tool" for Unix based systems (i.e. Linux & Mac) to let your already
   installed McStas 1.x or 2.0 co-exist with the new 2.1
 - Using McStas with NeXus does no longer require recompilation if you only want to _write_ NeXus.
   (Simply install NeXus and update your MCSTAS_CFLAGS to include -lNeXus -DUSE_NEXUS). For the
   conversion of files using mcformat NeXus must still be available at compile time

 Core & runtime code:
 - Backward compatibility 1: As written above, STATE and POLARIZATION parameters are no longer supported!
 - Complete rework of the DETECTOR_OUT infrastructure:
   * Simplified code-structure
   * Proper support for MPI when generating NeXus event lists
 - New logic wrt. negative time propagation: Neutrons are restored rather than ABSORB'ed
 - Improvement of the interpolation routines e.g. for magnetic fields: search is performed roughly in constant time
 - Read_Table: better search for files, including from full executable path, from source.instr location, from 
   PWD and from McCode lib.
 - ref-lib.c: If components use alpha=0 and w=0 in parametrizing the reflectivity, the StdReflecFunc
   applies a phenomenological fit of Swiss Neutronics mirrors (above m=3 including a 2nd order beta term). The fits
   were done by Henrik Jacobsen, University of Copenhagen.

 - Since 2.0 mcgui Perl and mcrun Python has been generating time-stamped output directories if no output dir 
   was specified. The legacy mcrun Perl now exhibit this behavior also. This is balanced by the possiblitiy
   to choose . (dot) as the output directory - then the legacy behaviour of storing data in the working
   directory is enabled.

 - Modernized and facelifted TeX documentation in the manuals, which include slightly updated Component manual.
   A few components-docs parameter tables are now extracted from mcdoc and included in the manual. 

 New Components:
 - Rotator and Derotator - components that allow a section of the instrument to rotate in time.
 - New ESS_moderator component by P Willendrup, E Klinkby and T Schoenfeldt DTU
   * new ess_source-lib with brilliance defintitions corresponding to Mezei 2001, TDR and 2014 brilliances
   * support for geometrical brilliance variation (i.e. "pancake" geometry)
   * much simplified input-parameter setup
   * various fixes wrt. McStas 2.0 and later updated source modules
 - Monitor_Sqw - generates an Sqw between a sample and a detector, a kind of inelastic resolution monitor.
   (Emmanuel Farhi)
 - Analyzer_ideal.comp, ideal analyzer for Spin-Echo techniques (Erik Knudsen)
 - Pol_pi_2_rotator.comp, idealized pi/2 flipper for Spin-Echo (Erik Knudsen)
 - Pol_triafield.comp, idealized triangular coil (Delft) for Spin-Echo (Erik Knudsen)
 - Scatter_log_iterator.comp, see above notice about "Scatter logging"
 - Scatter_log_iterator_stop.comp, see above notice about "Scatter logging"
 - Scatter_logger.comp, see above notice about "Scatter logging"
 - Scatter_logger_stop.comp, see above notice about "Scatter logging"
 - SANS_benchmark2.comp, benchmarked SANS component from Heinrich Frielinghaus, FZJ

 Updated Components:
 - Single_crystal and PowderN have both been optimized for speed - especially in connection with using
   the SPLIT keyword:
     * The first precomputations relating to structure and crossections is kept for each incoming netron,
       so that the component may skip these calculations for the next SPLIT version of the neutron (there
       is a built-in check for whether that kind of neutron was processed before). This means that a set'
       of SPLIT neutron may be scattered across ALL reflection that are allowed for that specific incoming
       direction and wavelength. Further, the components estimate the optimal value of the SPLIT. For large
       single crystal unit cells (i.e. protein crystals etc.), speedups of a factor of 500 have been observed!
       The method works with all orders of scattering, even though the largest gain is seen with order=1.
     * Use is easy, e.g.
          SPLIT 43 COMPONENT SX=Single_crystal(order=1, ...)
 - Single_crystal now allows to be used as a Powder, mainly for benchmarking purposes - at the point of scattering,
   the "crystallite" is randomly oriented. Final validation is pending, but in this setting, the component already
   gives the same order of manitude scattering as PowderN, where this powder ring "intergration" has been 
   implemented using a completely different strategy - provided the right values of mosaicity and delta_d_d are
 - ISIS moderator component allow specification of the accellerator current. The component performance
   defaults to the actual, relevant accellerator setting for each target station (TS). All TS1 and TS2
   moderator input files are now included with McStas and have meaningful names with reference to the 
   relevant TS. 
 - Source_gen now contains LLB and FRM-II source parameters in the component help.
 - Monitor_nD contains infrastructure for handling events in Mantid NeXus files.
 - Isotropic_Sqw - various fixes, including optimized memory usage
 - Lens component - support for abstract geometries via the OFF/PLY input format
 - Guide_anyshape - various improvements
 - FermiChopper - fixed bug in tangent intersection
 - Elliptic_guide_gravity - support for curvature via horizontal, vectorial addition to gravity

 - Various instruments have been included, allowing to estimate pulsed-source average and peak brilliance.
 - ISIS_SANS2d instrument contributed by R. Heenan, ISIS
 - Test_Guide_Curved - test instrument for simple, curved guide types
 - HZB_FLEX contributed by Klaus Habicht and Markos Skoulatos, HZB
 - SEMSANS_instrument.instr by Morten Sales, HZB
 - Test_Scatter_log_losses.instr, see above notice about "Scatter logging"
 - Test_Scatter_log_mvalues.instr, see above notice about "Scatter logging"
 - Test_Scatter_log_ssw_mcnp.instr, see above notice about "Scatter logging"
 - FZJ_BenchmarkSfin2.instr by Heinrich Frielinghaus, FZJ. Test instrument for the SANS_benchmark2.comp
 - templateNMX.instr, templateLaue variant demonstrating the Single_crystal speed improvement mentioned above

 - New .lau datafiles for macromolecular structures Rubedoxin and Perdeuterated pyrophosphatase, contributed by
   Esko Oksanen, ESS.

Changes in McStas v2.0, December 21st, 2012

 McStas 2.0 is the long-awaited major release of McStas

 - Thanks to all contributors of components, instruments etc.! This is what Open Source
   and McStas is all about!
 - Thanks to Johan Brinch for helping us modernize the structure of the code and bring
   new solutions in the tool area!
 - Thanks to Esben Klinkby for debugging results of the McStas (physics) test!

 - As documented in the manual, a new major release means loss of backward compatibility.
   See remarks below about STATE_PARAMETERS and naming of component parameters. Most of your
   existing instruments and components should be trivial to port to the new release as the
   code generation gives you helpful debugging information. Should you fail after trying, 
   feel free to send us a tgz or zip with all needed instrument- and component code to and we will try to help.
 - As of this release, McStas is distributed as multiple packages rather than a monolithic:
   - mcstas, contains code generator and runtime codes
     * Dependencies: a C-compiler (and mcstas-comps)
     * Optional: an MPI environment
   - mcstas-comps, contains component- and instrument example libraries 
     * Dependencies: mcstas
   - mcstas-tools-Perl, contains our "legacy" set of perl tools 
     * Dependencies: mcstas, Perl, Perl::Tk, pgplot, perl-PGPLOT, Gnuplot
     * Optional: Perl::Tk::CodeText, Perl::Math::Amoeba, Matlab, a VRML-viewer, (Scilab 4.0)
     * Remark: As far as possible, we provide dependencies in the installation bundles
     * Remark: mcgui can be configured to run python-based tools for sub-tasks
   - mcstas-doc, contains our PDF manuals
   - mcstas-tools-Python-mcrun, contains our new, python-based compile/run script
     * Dependencies: python-yaml
     * Remark: The script falls back to the perl version if dependencies do not resolve
   - mcstas-tools-Python-mcplot-matplotlib, contains a new matplotlib mcplot solution
     * Dependencies: python-matplotlib
     * Remark: A bit on the slow side for large datasets
     * Remark: Features zooming on individual plots
     * Remark: "Standard" mcplot shortcuts for graphics dumps etc.
     * Remark: Recommendations for platform-specific python-distributions below
     * Remark: The script falls back to the perl version if dependencies do not resolve
   - mcstas-tools-Python-mcplot-chaco, contains a draft implementation of mcplot based on chaco
     * Dependencies: python-chaco
     * Remark: Faster than matplotlib-solution, but a bit on the slow side for large datasets
     * Remark: Features zooming on individual plots
     * Remark: Recommendations for platform-specific python-distributions below
     * Remark: Not easy to install dependencies for chaco if not in your python distro
     * Remark: The script falls back to the perl version if dependencies do not resolve
   - mcstas-web, contains a webserver-based run/trace/plot solution
     * Dependencies: python, python-XXX, R or perl+pgplot+perl-PGPLOT, nginx or apache
     * Remark: Currently not packaged, get it from our SVN.
 - In the future, we will release new versions of e.g. the component library, docs or tools while 
   maintaining the core mcstas package. See repository-remarks below.
 - A given McStas 2.x release is "self-contained" and can be installed in parallel with other of
   McStas and McXtrace (i.e. run mcgui-2.0RC2 to select a specific version)
 - We provide the new mccode-select and mccode-select-bundle that allows to select the version of
   a given tool (i.e. mcrun) which is run by default 
 - We provide a "migration tool" for Unix based systems (i.e. Linux & Mac) to let your already
   installed McStas 1.x co-exist with the new 2.x 
 - Using McStas with NeXus does no longer require recompilation if you only want to _write_ NeXus.
   (Simply install NeXus and update your MCSTAS_CFLAGS to include -lNeXus -DUSE_NEXUS). For the
   conversion of files using mcformat NeXus must still be available at compile time

 Platform support:
 - We have moved from autoconf+make to CMake for easy multi-platform support
 - Supported platforms / targeted distributions of McStas are available for
   - Debian-based Linux systems (including Ubuntu, Mint etc.)
     * Versions: 32 and 64 bit
     * Remark: Dependencies resolved through OS package system
     * Remark: We provide debian packages for dependencies that are not in the OS'es by default
     * Remark: On Debian you need to enable the 'non-free' and 'contrib' apt-repositories
     * Remark: We will soon provide an apt repository for your sources.list
   - RPM-based Linux systems (including Scientific Linux, CentOS etc.)
     * Versions: 32 and 64 bit
     * Remark: Dependencies resolved through OS package system
     * Remark: For most of these distros you will need to enable the RPMforge and EPEL repositories.
       	       See e.g.:
     * Remark: We provide RPM or SRPM packages for dependencies that are not in the OS'es by default
     * Remark: We will soon provide an RPM repository for your yum
     * Remark: The 'python-chaco' dependency for the chaco-mcplot is not easily available here
   - Mac OS X, through a set of .pkg packages
     * Versions: Independent 64 bit versions for 10.6 Snow Leopard, 10.7 Lion and 10.8 Mountain Lion. 
       	       Older versions are not directly supported, but installation should be possible if you 
	       build from the SVN tree using cmake.
     * Remark: On 10.6 you need to install a compatible Xcode - available from
       	       or use the one on your original installation medium.
     * Remark: On 10.7 and 10.8 you need to get Xcode from the App store and through the in-app preferences
       	       download the 'Command Line Tools'.
     * Remark: On 10.8 you need to install XQuartz from
     * Remark: We distribute dmg images for each supported target release of OS X including all other
       	       bits you need for runing McStas and the Perl tools. Follow instructions in the README file. 
     * Remark: To run the python-mcrun tool you need to install python-yaml via and this commmand:
               sudo easy_install pyyaml
     * Remark: To run the python-mcplot tools you need to either get
       	       a) Enthought Python (Commercial Python distribution) from .
	       	  This enables both the matplotlib and chaco based mcplot tools. You need to make the installed 
		  python the system-default python 2.7, the instructions from Enthought:
	       b) SciPy superpack from . This enables the 
	          matplotlib mcplot tool with the default Python available on OS X.
   - Microsoft Windows systems
     * Versions: 32 and 64 bit, tested on XP, Windows 7 and Windows 8
     * Remark: We distribute zip files for each 32 and 64 bit Windows independently. Follow instructions 
       	       in the README file. 
     * Remark: We recommend using Strawberry Perl (v. 5.16) and provide compatible ppd's for the various
               perl-tool dependencies (perl-PDL, pgplot, perl-PGPLOT, perl-Tk-CodeText, perl-Math-Amoeba).
	       Get Strawberry Perl via
     * Remark: Strawberry Perl includes gcc! Hence no need to install a separate c-compiler!
     * Remark: For MPI parallelization, we recommend installing MPICH2 from
     * Remark: We recommend Python(x,y) on Windows systems as it includes both matplotlib and chaco. Get
       	       Python(x,y) via
     * Remark: To enable the Python based mcrun tool with Python(x,y) you need to install PyYAML from
     * Remark: Windows installations now recide in e.g. c:\mcstas-2.0RC2 and we provide two version-
               dependent desktop links: mcgui-2.0RC2 and mcstas-environment-2.0RC2 (the latter for running 
	       simulations using the windows cmd.exe). We do not touch the system registry for setting up 
	       PATH's etc., all is handled from the two links/batch files.
 - As far as possible, we build the packages on "standard" versions of the relevant OS'es (with the exception
   of the windows builds that are created on Debian Linux via cross-compilation)

 - Many new developments as mentioned above. Just to name a few:
   - New mcrun tool based on Python
   - New mcplot tool based on Python+matplotlib
   - New mcplot tool baded on Python+chaco
   - New web-frontend based on Python
   - Mcgui perl-tool has been refurbished, updated look plus new button for changing working dir

 Core & runtime code:
 - Backward compatibility 1: Some backward-compatibility is lost in the new version of the code-generation, 
   as we no longer use the information defined in the component STATE_PARAMETERS and POLARISATION_PARAMETERS
   macros. A warning is issued in case of components using these macros, e.g.:
   Warning:  /usr/local/lib/mcstas-2.0delta/monitors/TOF2Q_cylPSD_monitor.comp is using STATE PARAMETERS
    mcstas-2.0delta 2.0delta support is PARTIAL for these and support will END with next release
 - Backward compatibility 2: We have standardized naming of component parameters - see the file NOMENCLATURE
   installed in the McStas library. The code generation will give error messages of e.g. using xw and yh where
   one should now be using xwidth and yheight.
 - Support for tabulated magnetic fields. New code for handling interpolation in sparse data is included 
   in the share/interpolation/ area. The test instrument Test_pol_tabled.instr takes use of this feature. 
   The curren implementation is in draft status, we expect speedup in the next McStas release.

 New Components:
 - Sample_nxs.comp from Mirko Boin, HZB. Diffraction/imaging oriented sample where one defines the structure
   by means of the NXS crystallography library which is now also included with McStas. The component comes with the test-
   instruments Test_Sample_nxs_diffraction.instr and Test_Sample_nxs_imaging.instr. 
 - Elliptic_guide_gravity.comp from Henrik Carlsen, NBI. Analytical approach to describing an elliptical guide
   geometry where gravity is taken into account. Included in the Reflectometer.instr from Anette Vickery, NBI.
 - Suite of SANS-samples from Martin Cramer Pedersen, NBI. Various approaches to describing SANS diffraction
   e.g. using the PDB data bank. Component names are SANSShells.comp SANSPDBFast.comp SANSPDB.comp 
   SANSNanodiscsWithTagsFast.comp SANSNanodiscsWithTags.comp SANSNanodiscsFast.comp SANSNanodiscs.comp
   SANSLiposomes.comp SANSEllipticCylinders.comp SANSCylinders.comp SANSCurve.comp SANSSpheres.comp. Included
   (some as comments) in the TestSANS.instr.
 - SANSQMonitor.comp also from  Martin Cramer Pedersen, NBI. Q-monitor for SANS also included in TestSANS.instr.
 - TOF2Q_cylPSD_monitor from Anette Vickery, NBI. Time-of-flight vs. q monitor of cylindrical shape. Included
   in the Reflectometer.instr test instrument. 
 - SNS_source_analytic.comp from Franz X. Gallmeier, SNS. Smooth-fit description of the SNS-moderators. Fits are
   derived from the same underlying raw-data as the ordinary SNS_source.comp is using directly with linear
   interpolation. NOTE: This component uses the atypical neutrons/pulse intensity unit. The used input file MUST 
   be given with a full path.
 - Brilliance_monitor.comp from Peter Willendrup, DTU Fysik. Monitor for easy evaluation of mean and instantaneous
   source brilliance for source comparison. Used in the ESS_brilliance.instr test instrument.
 - TOF_PSD_monitor_rad.comp from Kim Lefmann, KU. Derived from PSD_monitor_rad by Henrich Frielinghaus, FZJ.
   Position-sensitive TOF monitor with radially averaging.
 - PSD_TOF_monitor.comp from Peter Willendrup, DTU Fysik. PSD-monitor with a number of independent time-slices. 
   Derived from PSD_monitor by Kim Lefmann, KU.
 - Source_gen4.comp from Jonas O Birk, NBI and Uwe Filges PSI. Version of source_gen with PSI-specific changes,
   e.g. a high-energy tail contribution. Included in the RITA-II.instr from Linda Udby, NBI.
 - Absorber.comp from Peter Willendrup, DTU Fysik. Slab of perfectly absorbing material. Included in the RITA-II.instr 
   from Linda Udby, NBI.
 - PSD_monitor_psf.comp and PSD_monitor_psf_eff.comp from Kim Lefmann and Linda Udby, KU. Two derivatives of 
   PSD_monitor.comp both with gaussian point-spread-function and _eff with a 1/k efficiency parameter. Included 
   in the RITA-II.instr from Linda Udby, NBI.
 - Virtual_mcnp_ss_input.comp and Virtual_mcnp_ss_output.comp from Esben Klinkby, DTU Nutech. Allows to read and write
   MCNP/MCNPX 'source surfaces'. For use in simulations where neutrons need transport in both codes.
 - Virtual_mcnp_ss_Guide.comp from Esben Klinkby, DTU Nutech. Single guide piece sitting in a 'sandwich' between 
   an input and an output MCNP/X source surface.
 - Mirror_Curved_Bispectral.comp and Mirror_Elliptic_Bispectral.comp from Henrik Jacobsen, KU. Mirrors for the
   bispectral ESS instrument ESS_2001_bispectral.instr.
 - Radial_div.comp from Kaspar Klenoe, KU. Divergence monitor measuring the radial deviation in divergence. Used in 
   Henrik Jacobsen's ESS_2001_bispectral.instr.

 Updated Components:
 - ESS_moderator_long.comp patches from Kim Lefmann KU (multiple-pulses, TOF-focusing) and Esben Klinkby DTU Nutech 
   (geometry and spectrum from ESS MCNPX models). Thanks to Klaus Lieutenant from Vitess/HZB for providing adjusted
   parameters for the 'Mezei moderator' and a wavelength-dependent corretion term. The legacy 2001 ESS parametrization
   is provided in obsolete as ESS_moderator_long_2001.comp.
 - Bugfix of the SNS_source.comp from Garrett Granroth, SNS (segfaulted on windows). NOTE: This component uses the 
   atypical neutrons/pulse intensity unit. The used input file MUST be given with a full path.
 - Bugfix of the Multilayer_sample from Rob Dalgliesh, ISIS. 
 - Many other components received updates... 

 - HZB_NEAT.instr from Emmanuel Farhi, ILL - written in collaboration with Ruep E Lechner. The NEAT spectrometer
   from the HZB.
 - TestSANS.instr from Martin Cramer Pedersen, NBI. Test SANS setup for the new SANS components described above.
 - Reflectometer.instr from Anette Vickery, NBI. Reflectometer on pulsed source. Test instrument for a couple of
   components from NBI contributors decribed above.
 - Test_Sample_nxs_imaging.instr and Test_Sample_nxs_diffraction.instr from Mirko Boin, HZB. Test instruments for
   the use of Sample_nxs.comp. NOTE: Special compilation required, see instrument source codes!
 - RITA-II.instr from Linda Udby, NBI. Very detailed and complete, experimentally benchmarked description of the
   RITA-II spectrometer at PSI. Use the script for test-scans.
 - Test_SSR_SSW.instr and Test_SSR_SSW_Guide.instr from Esben Klinkby DTU Nutech. Test instruments for the above
   mentioned components.
 - ESS_2001_bispectral.instr from Henrik Jacobsen, KU. Model of a bispectral extraction system for the ESS (currently
   using the 2001 version of the source)
 - ILL_D22.instr from Emmanuel Farhi. Model of the D22 SANS from ILL.

Changes in McStas v1.12c, June 3rd, 2011

 McStas 1.12c is bugfix release.

 Bugfixes include:

  - Fix of a bug in the rectangular focusing routine, reported to mcstas-users by Markos Skoulatos, HZB
  - Introduction of --ncount as unsigned long long int in place of double. Using double could potentially lead 
    simulations to "hang". A re-release of McStas 1.12c was done due to bugs in components related to the new
    type returned from mcget_ncount.

  - If gnuplot is available at installation time, mcplot and mcgui can use this in place of PGPLOT.
    To use gnuplot, either
    - edit your mcstas_config.perl and put      PLOTTER => 'Gnuplot',
    - set the enviroment variable MCSTAS_FORMAT to Gnuplot

  - Lens.comp, typo in author name corrected
  - Guide_four_side.comp (and other similar), by Tobias Panzner updated
  - Single_crystal.comp, corrected initialization when providing lattice consts and angles
  - Source_simple.comp, corrected centering-bug when using gaussian wavelength distribution
  - Monochromator_pol.comp, now works properly in GROUPS/multi-slab configurations
  - Pol_simpleBfield.comp, potential polarisation exit-state bug corrected
  - FermiChopper.comp, fixed error when computing automatic phase 
  - Monitor_nD.comp, fixed geometry bugs reported by Lambert van Eijck
  Example instruments
  - ESS_IN5_reprate.instr, parameter naming change in ESS_moderator_long component was not accomodated.
  - templateTAS.instr, fixes relating to inclusion in other instrument files

Changes in McStas v1.12b, July 15th, 2010

 McStas 1.12b is mostly a bugfix release, and the VERY last release in the 1.x series.
 - A few extra features and contributions have been included.

 McStas 2.0 will be released late 2010 and will introduce new features that
 could break ceartain backward compatibility, hence we move from the 1.x series.

 Bugfixes include:

  - Further adjustments to the MPI implementation, solves problems of hanging processes on large cluster runs.
  - Threading support completely removed.

  - New contributions
    - Multilayer_Sample.comp (Robert Dalgliesh, ISIS)
      Multilayer Reflecting sample using matrix Formula. Requires GSL (GNU Scientific Library)
    - Lens.comp (C. Monzat/E. Farhi/S. Desert/G.Euzin, ILL/LLB)
      Refractive lens with absorption, incoherent scattering and surface imperfection.
    - Lens_simple.comp (Henrich Frielinghaus, FZ Juelich)
      Rectangular/circular slit with parabolic/spherical LENS
    - Guide_four_side.comp (Tobias Panzner, PSI)
      Models a guide with elliptic, parabolic or straight shaped side walls. 
    - Guide_four_side_2_shells.comp (Tobias Panzner, PSI)
      Models a guide with elliptic, parabolic or straight shaped side walls. 
      As -"- with 2 outer mirror layer shells.
    - Guide_four_side_10_shells.comp (Tobias Panzner, PSI)
      Models a guide with elliptic, parabolic or straight shaped side walls.
      As -"- with 10 outer mirror layer shells.
    - Pol_FieldBox (Peter Willendrup)
      Easier to use precession area. Corresponds to a set of Pol_simpleBfield's plus slits.
    - Sapphire_Filter (Jonas O Birk, Uni CPH). Filter component, defaulting to saphire material properties

  - New component features
    - Addition of high-energy tail to Source_gen.comp (edits by Uwe Filges, PSI)  
    - Single_crystal.comp extended for anisotropic mosaicity (EXPERIMENTAL), (edits by Erik Knudsen, Risoe DTU)

  - Various minor bugfixes to
    - Guide_curved.comp
    - DiskChopper.comp
    - SNS_source.comp
    - ESS_moderator_long.comp
  Example instruments
  - New examples
    - ISIS_CRISP.instr, CRISP reflectometer from ISIS, test instrument for Multilayer_Sample.comp above
    - Test_Lens.instr, test instrument for Lens.comp above
    - FZJ_KWS2_Lens.instr, KWS2 SANS from FZJ, test instrument for Lens_simple.comp above
    - templateTOF.instr (Was ILL_TOF_Env before)
    - templateLaue.instr (Derived from the old tutorial Laue instrument)
    - SE_example.instr and SE_example2.instr, simplistic Spin-Echo machines for illustrating use of Pol options
    - template.instr ("Void" instrument skeleton - like Insert->Instrument Template)
    - Test_shellguides.instr, test instrument for contributions from Tobias Panzner and Jonas O Birk.

  - Minor improvements to
    - templateDIFF.instr (SPLIT improves statistics)
    - templateTAS.instr (SPLIT improves statistics)
    - SNS_test.instr (Cleanup)
  - Added SNS moderator input file source_sct091_tu_02_1.dat
  - Added ISIS moderator input file h.crisp

  - We have decided to distribute the components and the other runtime code under the LGPL license (see the LGPL
    file under lib/ . This allows to link (unmodified) code from that directory with other software and achieve
    non-GPL binaries.
  Platform support/Tools
  - Mac OS X 10.3 Panther, 10.4 Tiger, 10.5 Leopard, 10.6 Snow Leopard (PPC/Intel, 32/64bit)  
    - Fix for problems with multiple perl installs, currently locked to perl 5.8.
    - Instructions for using Matlab visualisation in the .dmg README file
  - Windows XP 32/64bit, Windows Vista 32/64bit, Windows 7 32/64bit
    - Note that we provide only a 32 bit package, but shown to work on 64 bit
    - Fixed mcrun / mcgui for Windows for missing transfer of mpi parameters
    - Fixed mcplot for Windows, foreground color is now black, not cyan
  - Linux: Ubuntu is now our only "reference" Linux (Debian does not provide perl-pgplot)
    - Ubuntu .deb's for 32 and 64bit, work for both for 9.10 Karmic Koala and 10.04 Lucid Lynx
    - The .deb's require PGPLOT and perl-pgplot from Ubuntu Universe/Multiverse repositories

  - Improved stability of MPI simulations
  - A number of unlisted minor bugs ironed out, both in components, runtime code and tools.

 McStas 1.12a is essentially a bugfix release, and the last release in the 1.x series.

 McStas 2.0 will be released late 2009 / early 2010 and will introduce new features that
 could break ceartain backward compatibility, hence we move from the 1.x series.

 Bugfixes include:

  - Adjustments to the MPI implementation, solves problems of hanging processes on large cluster runs.

  - Various minor bugfixes to
    - Isotropic_sqw.comp
    - Vitess_input.comp
    - Pol_bender.comp
    - Pol_monitor.comp
    - PolLambda_monitor.comp
    - SNS_source.comp
    - ISIS_moderator.comp
    - FermiChopper_ILL.comp
    - Progress_bar.comp
    - TOFRes_sample.comp
    - Virtual_tripoli4_output.comp
    - Guide_honeycomb.comp
  Example instruments
  - Minor improvements to
    - PSI_DMC.instr (source-guide focusing corrected)
    - templateDIFF.instr (SPLIT improves statistics)
    - templateTAS.instr (SPLIT improves statistics)
    - SNS_test.instr (Cleanup)

  - Added SNS moderator input file source_sct091_tu_02_1.dat

  - Fixed mcrun / mcgui for Win32 for 'fixed --ncount at 1e6' when scanning/optimizing
  Platform support
  - Mac OS X, fix for problems with multiple perl install
  - Windows XP,  Windows Vista - see Tools section
  - Linux, pgplot and pgperl now builds using gfortran (replacing g77)
  - Improved stability of MPI simulations
  - Preference for OpenMPI (standard on Ubuntu and Mac OS X)

  - A number of unlisted minor bugs ironed out, both in components, runtime code and tools.

Changes in McStas v1.12, May 8th, 2008

  - New %include "instr" mechanism to include one instrument in another. (Useful for independent
     build-up of e.g. primary and secondary spectrometer. Or easily see the effect of moving an instrument
     to a different beamport or facility!) See the manual for details.
  - When applying the WHEN keyword, an applied EXTEND %{ %} block will only be active if the WHEN
     returns 'true'.
  - Please take care when combining WHEN, GROUP and EXTEND %{ %} - see the manual.

  - Fix of a limiting case focusing problem reported to mcstas-users by George Apostolopoulos.
     ( See )

  - When using the Virtual_input type components, --ncount is always set to an integer multiplum 
     (repeat_count) of the number of events in the file. See also related remark about MPI below.
  - New component: MirrorElli.comp, elliptical mirror. Contributed by Sylvain Desert, LLB
  - New component: MirrorPara.comp, parabolic mirror. Contributed by Sylvain Desert, LLB
  - Single_crystal validation still ongoing, but has progressed: The algorithm seems OK, but is to some
     extent not in sync with the documentation. New option to specify reciprocal space vectors directly.
     (before only real space definitions were possible)
  - Most monitors now allow to 'not propagate' the neutron, i.e. not influence the beam. Parameter name
     is 'restore_neutron'.
  Example instruments
  - ILL_H25_IN22_sample/_resolution.instr (CRG instrument @ ILL) by E. Farhi / P. Willendrup
  - Incoherent_Test.instr - instrument to compare incoherent scattering from the different sample comps
     (V_samle, PowderN, Single_crystal, Isotropic_sqw). More instruments of this type planned (compare
     guides etc.), P. Willendrup / E. Knudsen / A. Daoud-Aladine
  - FocalisationMirrors.instr - test instrument for MirrorElli and MirrorPara, Sylvain Desert, LLB
  - PSI_DMC.instr, Powder Diffractometer, PSI, L. Keller / U. Filges / P. Willendrup

  - 'Bugfix', some of the provided .laz files did not have proper unit for |F2|.
  - Support for per-user mcstas_config.perl file, located in $HOME/.mcstas/ . This folder is also the default
     location of the 'host list' for use with MPI or gridding, simply name the file 'hosts'.
  - mcgui Save Configuration for saving chosen settings on the 'Configuration options' and 'Run dialogue'.
  - Possibilty to run MPI or grid simulations by default from mcgui.
  - When scanning parameters, mcrun now terminates with a relevant error message if one or more scan steps
     failed (intensities explicitly set to 0 in those cases).
  - When running parameter optimisations, a logfile (default name is "mcoptim_XXXX.dat" where XXXX is a
     pseudo-random string) is created during the optimisation, updated at each optim step.
  - We now provide syntax-highlighting setup files for vim and gedit editors.

  Output formats
  - Rudimentary support for GNUPLOT when plotting with mcplot. Data file format is standard McStas/PGPLOT.
  Platform support
  - Mac OS X 10.3 Panther (ppc), 10.4 Tiger (pcc/intel), 10.5 Leopard (ppc/intel)
  - Windows XP,  Windows Vista (Now with a recent perl version; 5.10 plus various fixes). New feature on Windows:
     Simulations _always_ run in the background, freeing mcgui for other work.
  - "Any" Linux - reference platforms are Ubuntu 8.04 (and earlier) and Debian 4.0 (and earlier). We have also tested 
     Fedora 8, OpenSuSE 10.3 and CentOS 4 releases recently.
  - FreeBSD (FreeBSD release 6.3 and its cousin DesktopBSD 1.6 recently tested)
  - SUN Solaris 10 (Intel tested, Sparc probably OK)
  - Plus probably any UNIX/POSIX type environment with a bit of effort...
  - Improved stability of MPI simulations by addition of an 'MPI barrier' (reduces probability of nodes beeing 'out of sync'.
  - On Windows, an 'mpicc.bat' script has been added for easier setup of McStas with gcc and MPI (We recommend MPICH).
  - Mac OS X 10.5 Leopard is shipped with built-in support for MPI (OpenMPI). No need to install extra packages.
  - Use of 'virtual sources' is now supported on MPI clusters. (If running on N nodes, all neutron events will be processed
     on each of the N nodes - implicit repetition N times of the source contents.)
  - OpenMP threading support 
  - Much improved gridding support (via ssh). Ready for heterogenous systems, e.g. mixed operating systems and hardware
     types! (Requires -c compile flag for mcrun or equivalent setting in mcgui.) The only requirement is ssh client on the machine 
     where the grid run is started, plus ssh daemon and c-compiler (e.g. gcc or simply cc) on the remote machines. Files in the 
     current dir are transparently copied back and forth, causes a substantial network traffic in some cases. Output data from the 
     nodes are automatically merged using mcformat. Just as efficient as MPI without any library dependencies at all. Make use 
     of all processer cores in your machine, simply choose to 'grid'. Windows 'client' host OK, we autodetect ssh and scp binaries
     from the Putty package.

  - A number of minor bugs ironed out, both in components, runtime code and tools.
  - From release 1.12, McStas is GPL 2 only. The debate on the internet about the future GPL 3 license suggests that this license 
     might have implications on the 'derived work', hence have implications on what and how our users use their McStas simulations
     for. To protect user freedom, we will stick with GPL 2.     

  WARNING: The 'dash' shell which is used as /bin/sh on some Linux system (Including Ubuntu 8.04) makes the 'Cancel' and 'Update' 
  buttons fail in mcgui. Solutions:
  a) If your system is a Debian or Ubuntu, please dpkg-reconfigure dash and say 'no' to install dash as /bin/sh
  b) If you run another Linux with /bin/sh beeing dash, please install bash and manually change the /bin/sh link to point at bash.

Changes in McStas v1.11, July 3rd, 2007

  - New SPLIT keyword for improving statistics. WARNING: Follow instructions in the documentation for safe
    use of the SPLIT keyword. 

  - Source_adapt.comp, additions by Aaron Percival which allows to specify a flat wavlength distibution.
  - Single_crystal.comp, warning NOT to use this component as a monochromator (bug fix/validation under way).
  - PowderN.comp, can now be used in concentric mode, i.e. for modelling sample surroundings (cryostat, container..).
  - Tunneling_sample.comp (new) Double-cylinder shaped all-incoherent scatterer with elastic, quasielastic (Lorentzian)
    and tunneling (sharp) components. No multiple scattering. Absorbtion included. By Kim Lefmann
  - TOF2E_monitor.comp (new) TOF-sensitive monitor, converting to energy. By Kim Lefmann

  Example instruments
  - New ILL_H15_IN6 and ILL_H142_IN12 instruments by Emmanuel Farhi are included.
  - Histogrammer.instr - see the 'Tools' section
  - New ESS_IN5_reprate.instr Instrument for simulating IN5-TYPE (cold chopper) multi-frame spectrometer at ESS LPT.
    (Also example instrument for Tunneling_sample.comp.) By  Kim Lefmann

  - Reflectivity curves from Swiss Neutronics (more work done, available in the next McStas release).
  - More Sqw tables for use with the Isotropic_Sqw component.

  - PGPLOT output format (original McStas format) is now possible on Windows. A pgplot/pgperl installation
    is included in a standard McStas Win32 installation.
  - New mcdaemon for visualisation of intermediate simulation results (obtained by sending USR2 signal to a 
    running simulation or by using the Progress_bar component with flag_save=1).
  - Improvements to mcgui:
    * New tool menu with hooks to mcformat, mcdaemon and mcplot
    * Possibility for auto-setup of MPI ssh keys
    * Possibility to run the McStas editor in 'detached' mode, hence available whilst a simulation is running
  - Histogrammer.instr: Special histogramming instrument for visualisation of virtual source files (Virtual_input,
    VitESS, MCNP and Tripoli formats)

  Output formats
  - NeXus output format possible. To use this feature, HDF and NeXus libraries must be available
    and functional on your system before installing McStas from source. (In case of a binary package, 
    you MUST recompile the McStas software.) To enable a McStas build with NeXus, run 
    ./configure --with-nexus.

  Platform support
  - Mac OS X is now considered a supported platform. For now, no actuall installer program
    is given, but all needed software has been packed together with easy to follow instructions.
    Test of the instructions have been performed on Mac OS X 10.4 Tiger on both Intel and PPC
  - McStas now comes in a Debian binary package (.deb), tested to work on Debian and Ubuntu systems. The debian
    package provides McStas, pgplot and pgperl and have dependencies for the perl, perl-tk, gcc, libg2c0, pdl and libc6-dev 

  - The threading mechanism for parallelisation has been removed from McStas since it caused too many problems. For 
    parallelisation on single machines (e.g. modern dual-core processors) or clusters, MPI (MPICH) is the recommended solution.
    The McStas team members routinely run developer machines and clusters using MPI.

  Intel C compiler
  - The documentation now includes instructions to run McStas with the Intel C compiler (available on Windows,
    Linux x86 and Mac OS x86 systems). Typically, a performance gain of 2 is found relative to gcc -O2. Relevant
    compiler flags are:

    MCSTAS_CFLAGS="-g -O2 -wd177,266,1011,181"
    export MCSTAS_CC="icc"

  - To run McStas with MPI and the Intel C compiler, you may have to edit your mpicc shell script to set:

  - A standard McStas source package now works directly within the DANSE framework.

  WARNING: The 'dash' shell which is used as /bin/sh on some Linux system (Including Ubuntu 7.04) makes the 'Cancel' and 'Update' 
  buttons fail in mcgui. Solutions:
  a) If your system is a Debian or Ubuntu, please install our Debian package which requests automatic removal of 'dash'.
  b) If your /bin/sh is dash, please install bash and manually change the /bin/sh link to point at bash.

Changes in McStas v1.10, Dec 4, 2006

  - This release is a major step forward for McStas in terms of support for polarisation.
    Peter Christiansen who worked at Risoe March-October 2006 was the main workforce 
    behind this new functionality, backed by funding from ISIS, work by Rob Dalgliesh at 
    ISIS and inspiration from the VitESS and NISP packages. As this is the first release
    with polarisation support, the methods and algorithms implemented will certainly be 
    developed further. Hence, documentation of the functionality has been placed in an 
    appendix to the manual. 
    Polarisation users: Please give us feedback for further development!
    Items marked by (p) below relate to the new polarisation support.
  - New keywords for the meta language improves support for e.g. description of sample
  - A method for automatic optimisation has been implemented, e.g. for achieving maximum flux
    at the sample position (any quantity measured by a McStas monitor can be optimised) as a
    function of simulation parameters.
  - Bugfixes in many different areas.

  - Manual and component manual slightly updated according to adding/modification of components
    and functionality. New appendix on the polarisation features. (p)

  - New WHEN keyword, conditional use of components,
        COMPONENT MyComp=Component(...) WHEN (condition) AT
  - New JUMP keyword, possibility to iterate a given component a number of times (multiple 
    scattering) or for 'teleportation' to a given component. (USE WITH CAUTION)
  - Improved COPY keyword with parameter substitution (Make a copy of an other component 
    instance with a few parameters changed)
  - Spin propagation algorithm (When magnetic field is set 'on', the central propagation
    routines also handle Larmor precession in the field) (p)
  - Handeling of analytical B-fields (p)

  - New 'merge/convert' tool mcformat: Convert between McStas output formats and merge cluster
    node datasets into one dataset.
  - TOF mode for mcdisplay (Statistical chopper acceptance diagrams generated from the simulated
    neutron rays. Currently only supported on Unix systems with PGPLOT.)
  - Optmisation support in mcrun/mcgui using Perl::Amoeba (se description above)
  - POSIX threading on multi-core processors (BEWARE, performance is generally better using MPI)
  - mcgui: Note that if you experience crashes when starting/running GNOME/Gtk2 applications, 
    update your perl-Tk installation. Two ways to do this:
    1) Get the tarball from and
       install using 'perl Makefile.PL && make && make install'.
    2) Do a 'make tk' in the McStas unpacked McStas source directory. This will download and
       install the tarball into your McStas system directory.

  - Monochromator_pol.comp - Polarising monochromator/analyzer (p)
  - Pol_bender.comp - Polarising bender (p)
  - Pol_mirror.comp - Polarising mirror (p)
  - Pol_guide_vmirror.comp - Guide with semi-transparent, polarising mirror (p)
  - Pol_simpleBfield.comp - Numerical precession in analytical B-fields (p)
  - 3 Polarisation monitors - MeanPolLambda_monitor.comp, PolLambda_monitor.comp
    Pol_monitor.comp (p)
  - PSD_Detector.comp - Physical detector - comes with many gas lookup tables 
    (Contrib: Thorwald van Vuure, ILL)
  - Virtual_mcnp_*.comp - MCNP event file handeling
    (Contrib: Chama Hennane, ENSIMAG and Emmanuel Farhi, ILL) 
  - Source_multi_surfaces.comp - Source comp with multiple surface areas with individual
    (Contrib: Ludovic Giller, EPFL and Uwe Filges, PSI)
  - multi_pipe.comp - Defines a 'grid' of slits (focusing device)
    (Contrib: Uwe Filges, PSI)
  - Exact_radial_coll.comp - Radial collimator comp, exact model
    (Contrib: Roland Schedler, HMI)
  - FermiChopper_ILL.comp  - Fermi Chopper comp with optional supermirror coated blades.
    (Contrib: Helmut Schober, ILL)
  - V_sample enriched with quasi-elastic features (Kim Lefmann)
  Example Instruments
  - TAS frontend with reciprocal space (hkl) calculator (Emmanuel Farhi)
  - Example instruments for polarisation comps (p)
  - QUENS_test.instr (Test of new quasi-elastic features V_sample)
  - Much easier installation on Windows, single executable file with all support applications
    is now available. Simply click 'next' alle the way and you are done.
  - PGPLOT and Scilab installation help tools on Linux systems

  WARNINGS (Almost identical to those from release 1.9.1)
  - Because of rapid changes in the support software for McStas, the current release has support
    for only some releases of:

    * Scilab (Win32 and Unix) - pick release 4.0 if available or pick release 3.0 from , e.g. from
      (Automatically included in the Win32 .exe installer and Linux Scilab installer)

    * Perl (Win32) - on Windows we only support Perl 5.6 - pick
      (Automatically included in the Win32 .exe installer)

    * If you are running Unix with GNOME/Gtk2 applications, you may experience problems with mcgui
      crashing, please install updated perl-Tk from

Changes in McStas v1.9.1, Mar 29, 2006

  - Update release, mainly bugfixes plus a few other things

  - Component manual slightly updated according to adding/modification of components.

  - mcgui: A few bugfixes. Note also that if you experience crashes when starting/running
    GNOME/Gtk2 applications, update your perl-Tk installation. Two ways to do this:
    1) Get the tarball from and
       install using 'perl Makefile.PL && make && make install'.
    2) Do a 'make tk' in the McStas unpacked McStas source directory. This will download and
       install the tarball into your McStas system directory.

  - DiskChopper.comp - new disc chopper component. Chopper.comp made obsolete.
    See mcdoc page / component manual for further details.
  - Guide.comp - reads reflectivity tables from disk.
  - Isotropic_Sqw - minor bugfixes, validated against PowerN, V_sample, etc.
  - PowderN - validated against Isotropix_Sqw, Squires, experimental data.

  - Because of rapid changes in the support software for McStas, the current release has support
    for only some releases of:

    * Scilab (Win32 and Unix) - pick release 4.0 if available or pick release 3.0 from , e.g. from

    * Perl (Win32) - on Windows we only support Perl 5.6 - pick

    * If you are running Unix with GNOME/Gtk2 applications, you may experience problems with mcgui
      crashing, please install updated perl-Tk as noted above.

Changes in McStas v1.9, Nov 16, 2005

  - To indicate the collaborative nature of the McStas package, the main website
    URL does no longer belong to Risoe or ILL but is
  - The package has been strengthened by the presence of Klaus Lieutenant (former
    captain of Vitess, HMI) at ILL. He has focused a lot on validation and testing
    of the package, giving very important input and done very valuable work.
  - To help us in the fight against bugs, a BUGZILLA system has been set up for users
    to report their suggestions and problems. The system is available at the URL .
  - The VnCS (Virtual neutron Code Sharing) agreement has been signed by the leaders
    of the Vitess and McStas software packages to formally support closer collaboration
    and sharing of code between the packages. At least one component (Vitess_ChopperFermi)
    now works with both packages, work done by Klaus Lieutenant and Geza Zsigmond.
  - Many big and small BUGS ellimnated!
  - First attempt at "concentric components" (sample environment). See Isotropic_Sqw in
    the 'Components' section below.

  - With this release, the component manual has finally been updated! Major work has
    been put into this by especially Kim Lefmann and Emmanuel Farhi. The user manual
    has also been revised, but not as intensively.
  - Improvements to tutorial/teaching material as result of Copenhagen University course on
    neutron scattering, given by Kim Lefmann and Peter Willendrup. The idea is that when
    improved further, the full simulation part of the course can serve as an extended
    tutorial for McStas. In the package, projects on virtual experiments at DMC, RITA-2 and
    SANS-2 at PSI is included.

  - A web frontend is now available for McStas, check it out at .
    Currently it is not actually part of the package, may become so in a near future release.
  - On Unix systems, mcdaemon is a tool to periodically send -USR2 signals (save) to running
    simulation processes. Is in an early state but should work okay, but not documented in the
    user manual. Replots intermediate data.
  - mcgui has been intensively revised, many annoyances have been removed and features adjusted
    for easier use.

  - For simplicity, a number of components (especially monitors and sources) have been merged.
    This for example means that the Source_simple replaces the former Source_flat* components.
    Fewer duplications of code => smaller risk of old bugs surviving in the code.
  - PowderN: General powder sample component, replaces the simpler Powder1 and Powder2 components,
    has a very flexible system to read crystallographic data for powder line description. Is
    in the process of beeing validated against data from DMC@PSI. The code itself and the
    validation of it is the result of collaboration between mainly Peter Willendrup from the
    McStas team and Laurent Chapon (ISIS), Uwe Filges (PSI) and Lukas Keller (PSI). A validation
    paper will be presented at ICNS, Sydney.
  - Isotropic_Sqw: Originally work for the Ph.D. thesis of V. Hugouvieux, ILL. Extended and
    validated intensively by Emmanuel Farhi, ILL. It handles elastic and inelastic scattering
    for both coherent and incoherent processes, with secondary absorption and multiple scattering.
    The code has been validated against PowderN and V_sample. It comes with the same flexible
    system as PowderN to read data files, including crystallographic data for powder line
    description. Moreover, it may be used to describe concentric geometries in order to model
    sample environments.
  - Vitess_ChopperFermi: Originally work for Vitess by Geza Zsigmond, now PSI. Validated and
    adapted for use with McStas by Klaus Lieutentant, ILL in the frame of the VnCS agreement.
  - TOFRes_sample: time-of-flight version of the Res_sample component. Written by Kim Lefmann,
    Risoe. Will be merged with the res_sample component in next release.
  - The full suite of Fermi Choppers have been tested intensively by Klaus Lieutentant, partly
    inspired by the work of ILL stagiere Rebecca Peacock.

  - Because of rapid changes in the support software for McStas, the current release has support
    for only some releases of:

    * Scilab (Win32 and Unix) - pick release 3.0 from , e.g. from

    * Perl (Win32) - on Windows we only support Perl 5.6 - pick

Changes in McStas v1.8, Mar 4, 2004

  - McStas is now GPL software. Note that generated code, output data and papers
    based on these is not considered "derived work" but merely normal usage of the
    software package.
  - The McStas software package now includes a re-distribution of the plotlib
    package for Scilab, (, courtesy of
    Stephane Mottelet ( Plotlib is beeing distributed
    using a BSD like license. Plotlib needs not be precompiled anymore.
  - McStas now uses the Perl CPAN module Proc::Simple on unix platforms. Proc::Simple
    is distributed using the Perl artistic license.

  - Nightly CVS builds of McStas are now available to the public from (optionally use the mcsync script to get these)
    NOTE: The CVS builds are not considered 100% stable, you can count on errors
    in there, but you also get the newest stuff.

  - Improved installation and build scripts. NOTE: The new version is INCOMPATIBLE
    with Win32 releases older than Windows 2000
  - Automatic detection of plotting backend, (make config)
  - Test procedure (make test)

  Kernel (i.e. the 'mcstas' program)
  - a PREVIOUS keyword has been implemented, for referencing e.g. position placement
    to upsteam components.
  - improvements to runtime randvec_target_rect functions
  - Updated Mersenne Twister random number generator

  - Various bugfixes, especially on the Win32 platform and RedHat 9 specific stuff
  - mcgui now includes an option to 'scan' instrument parameters (previously only
    possible using
  - script has been added to the distribution, converts between
    Matlab and Scilab type output. Cyclic conversion, e.g. Matlab->Scilab->Matlab
    is not supported.
  - mcplot opens scan steps with Matlab/Scilab backends
  - mcrun now has support for Matlab/Scilab backends, built in test procedure
    (mcrun --test), poor man's grid computing - see the manual for information on
    how to use this.
  - mcdoc support for instrument headers, support for the built in tutorial
  - Improved tutorial built into the gui tools
  - editor, various improvements (line numbers etc.)

  - mcgui now has a special Neutron Site menu (auto generated) to allow distribution
    of instruments
  - instruments can now have default input values
  - several contributed / new instruments, have a look in your examples/ folder

  - New components:
    $ Official components
      - Sans_spheres, a sample for small angle neutron scattering
      - Powder2, a two ring powder sample
      - Phonon_simple, a phonon scattering sample
      - Guide_gravity improved
    $ Contributed components
      - Guide_tapering, guide with elliptical/parabolic/general tapering
        (Uwe Filges)
      - ISIS_moderator, (Stuart Ansell and Dickon Champion)
      - Guide_curved (Ross Stewart)

Changes in McStas v1.7, Jan 17, 2003

  Kernel (i.e. the 'mcstas' program)
  - components may have a SHARE section, which is imported only once per type
    of component. It has the same role as DECLARE, but only once.
  - the component files may have some %include inside '%{ }%' C DECLARE or SHARE
    blocks. The files to include are searched locally, and then in the library.
    If an extension is found, just the specified file is included, else both
    .h and .c are embedded if the --no-runtime has not been specified.
    The instrument files can also embed external files, both in C blocks
    and in the instrument parts (DECLARE, etc...) as in previous releases.
  - The instrument and components may have char* setting parameters. For
    instruments, their length is limited to 1024 chars.
  - The FINALLY section, that was executed at the end, has been split into
    still the FINALLY, and a new SAVE section. This latter is executed
    at simulation end (just before the FINALLY), but also each time an
    intermediate save is required (e.g. a 'kill -USR2 ' is used).
  - An instrument source file may contain EXTEND %{ }% C blocks just after
    the usual AT...ROTATED.. keywords, to extend the behaviour of existing
    components, without touching their code. All local component variables are
    available. This may for instance be used to add a new 'color' to neutrons,
    i.e. assign a new characteristic variable to the neutron.
  - component instances in an instrument source file may be GROUPed into
    exclusive assembly, i.e. only one component of the group will intercept
    neutron, the rest will be skipped. This is usefull for multi monochromators
    multi detectors, multiple collimators, ... This is a kind if splitting.
  - McStas can now compile for Windows without troubles (if lex/yacc files
    were generated elsewere, or using the flex/yacc for Windows)

  Run-time library (e.g. the instrument program)
  - A global gravitation handling is now available, by setting the -g flag
  - many output formats are available for data. use the --format="format"
    flag, e.g. --format="Scilab". The full list is displayed with
    the -h flag for the instrument program.
      mcrun test.instr --format="Matlab binary" -n 1e4
    will create a mcstas.m file. Launch Matlab and execute
      s=mcstas('plot')  % will import data into s, and plot all detectors.
    Binary formats are handled by IDL, Matlab, Scilab.
    The present available format list is
      "McStas" "Scilab" "Matlab" "IDL" "XML" "HTML"
    The default format is McStas/PGPLOT, but may be specified globally using
    the MCSTAS_FORMAT environment variable
  - It is possible to save 3D data arrays, by calling the DETECTOR_OUT_3D macro.
    (handled as 2D by mcplot)
  - The type of the 'number of events' array in monitors was changed from int to
    double, to avoid overflow. Please update your home-made monitors.
  - many dedicated libraries are now available as shared code for reading
    tables, handling data trees and monitors. These are C functions to be
    %included into components (see e.g. lib/monitors/Monitor_nD.comp)
  - The USR2 signal generates an intermediate save for all monitors, during
    the simulation (execute the SAVE section). The USR1 still give informations.
  - a new randvec_target_rect function now focuses on a rectangle
    (more efficient than former randvec_target_sphere=randvec_target_circle)

  Components (in the lib directory)
  - a new data directory contains neutron data tables
  - obsolete directory contains components that were renamed or old.
  - misc/Progress_bar component now exists, and may save data regularly.
  - optics/Monochromator_curved can read reflectivity and transmission tables
  - monitors/Monitor_nD can have automatic limits mode for either all or
    selected monitored variables. It may also plot banana monitors for mcdisplay
    and trigger intermediate savings for all monitors (same as USR2 sig.)
    Also, it may monitor something else than the intensity, e.g. the mean
    energy on a XY psd.
  - sources/Virtual_output can save all neutron events into a file
    (beware the size of the generated files !). Format may be text and binary
  - sources/Virtual_input can read the files generated by Virtual_output
  - optics/Guide_gravity can handle a 2D array of channels
  - optics/Filter_gen can read a table from a file and affect the neutron beam
    (replaces the obsolete 'Flux_adapter'). It may act as a filter or a source
  - samples: they now can all target towards any component, giving its index
    (no need to compute target_x/y/z vector, use e.g. target_index=+1)
  - samples/Res_monitor, Powder1 and V_sample may now have a sphere or box
    shape, and may focus to a circular or rectangular area

  - Matlab, Scilab and IDL may read directly McStas results if the simulation
    was executed with the --format="..." option (see 'Run-time' changes)
  - mcplot, mcdisplay, mcgui are now less dependent on the perl/pgplot installed
  - mcplot can plot a single simulation data file
  - mcplot, mcresplot, mcdisplay can output gif, ps and ps color. They also
    have integrated help (-h options), and may generate output files in a
    non interactive mode (read file, create output file, exit)
  - mcplot and mcdisplay work with Matlab, PGPLOT and Scilab plotters (set with
    the MCSTAS_FORMAT default setting, or -pPLOTTER, or PGPLOT if not set)
  - mcrun can not currently generate scan results in other formats than McStas
  - mcsats2vitess works now ok for converting a McStas component to a Vitess one

Changes in McStas v1.6.1 (beta), Feb 18th, 2002.

 - a bug was corrected for very small signal statistics automatic limits
   search in Monitor_nD (0.16.4), that could cause parasitc peaks and
   fluctuations in detector.

 - 'optics' components were renamed by categories, starting with Guide_...,
   Monochromator_..., Filter_... etc so that sorting is easier.

 - Monochromator_2foc and Monochromator_curved can now read a reflectivity table
   file (eg. PG) with rows [k, R]. Both components give the same results, and
   can use the same parameters.

 - mcplot can now read a list of detector files, without a '.sim' file. This
   enables to visualise a set of selected monitors, or may be used when the
   mcstas.sim file was deleted. Detector files must be in current directory.

 - the 1D and 2D detectors now compute simple signal statistics (min, max, mean,
   center and width of distributions) which are stored in the detector file
   and shown in plots (mcplot).

 - The Virtual_input replaces the Source_file component (see below), and can
   read text, Vitess and binary float files of neutron events.

Changes in McStas v1.6-ill (alpha), October 29th, 2001.

 - In component definitions, a SHARE keyword followed by a C code block
   %{...}% acts the same as a DECLARE block, but is only included once in an
   instrument. This is very useful when using many identical components
   (guides, monitors, monochromators) to speed-up compiling and perfomrnaces.
     %{ /* included only once for all identical components */
     %{ /* included for all components */
   Then all component programmers may add C functions to the 'kernel'. This is
   only worth when you plan to use a given component many times in a simulation
   (e.g. not for sources or samples). To downgrade a McStas 1.5 component, just
   move the SHARE block C code into the DECLARE block.
 - In an instrument definition, within the TRACE section, each COMPONENT
   instance may include a C code block:
     COMPONENT Comp1 = Guide(...)
     AT (...) ROTATED (...)
     %{ /* some C code to execute after component Comp1 */
        /* in current coordinate system. You may use Comp1 and global */
        /* instrument variables */
   For instance, you can here give a 'color' (additional neutron
   characteristic) and modify next components behaviours.
   This block is always executed in groups, but you can test if the componnet
   intercepted the neutron with the SCATTERED variable (if (SCATTERED) { ... }).
 - In an instrument TRACE section, it is possible to put a set of component
   in an exclusive group. Only one of the elements of the group can act on
   the neutron. If no element acts on the neutron, it is absorbed.
   This is specially useful for multi-detectors, multi-monochromators in
   parallel, multiple collimators/guides (e.g. radial).
     COMPONENT Comp1 = Guide(...)
     AT (...) ROTATED (...) GROUP MyGroupName

     COMPONENT Comp2 = Guide(...)
     AT (...) ROTATED (...) GROUP MyGroupName
   Comp1 and Comp2 may even be at the same place.
   For programmers: it is important that the component TRACE section contains a
   SCATTER keyword when it successfully intercepts it, to tell McStas that a
   component in a group acts on a neutron, and can skip other comp in the group.
 - In 'mcplot', it is possible to use the -ps, -psc and -gif options to
   generate a PS, color PS, and GIF file, and exit mcplot (no display).
 - The Monitor_nD was upgraded to correct bugs when reaching the component
   (the propagation was not performed correctly in some cases), and the disk/
   sphere radius (monitor remained then squared). This component now uses
   the SHARE block. A bug was corrected for lists. It can output log and abs of
   signals, and source files (see Source_file).
 - The Gravity_guide now handles correctly the focusing multichannel guides.
   Gravitation is included (on y axis). This component now uses the SHARE block.
   The Channeled_guide does not handle properly the focusing multichannels.
 - The Source_gen component focuses uniformly on the target, and can model
   rectangular, disk, gaussian, and Maxwellian (up to 3 distributions) sources.
   Previous source components did not focus correctly on the target. They were
   also corrected, execpt the 'Source_Maxwell'. Source_gen can replace all thee
   previous sources.
 - A new Source_file component can take as input a text file containing an
   array with columns ' x y z vx vy vz t sx sy sz p', such as the data files
   generated from Monitor_nD with options="list all source". The source may
   be re-generated more than once, which is useful to improve accuracy,
   specially when further components do MC choices. Vitess files and float
   binary files are also ok (auto-recognition of format).
 - The signal handler now gives more info about where a signal was caught.
   For instance it tells in which component part an error occured, to make
   debuging easier.
   Usefull Signals: kill -Signal 
      -USR1: display info and continue simulation
      -USR2: finish simulation and save results
      -QUIT: end simulation immediately
 - The 2D detectors now also output the errors/counts on signal as 1D detectors.
   Set p2=NULL in DETECTOR_OUT_2D to unactivate error saving in components.
 - We tried to lower the number of components by merging similar ones.
 - There are now new MACROS for the component programmer.
     * mccompcurindex is the number (index) of the current component
       (1 is first component of instrument)
     * RESTORE_NEUTRON(index, x, y, z, vx, vy, vz, t, sx, sy, sz, p)
       restores the neutron state to the one at the input of the component
       'index'. To ignore a component effect, use
       RESTORE_NEUTRON(mccompcurindex, x, y, z, vx, vy, vz, t, sx, sy, sz, p)
       at the end of its TRACE section, or in its EXTEND section.
       These neutron states are in the local component coordinate systems.
     * STORE_NEUTRON(index, x, y, z, vx, vy, vz, t, sx, sy, sz, p)
       stores the current neutron state in the trace-history table, in local
       coordinate system. This is automatically done when entering each
       component of an instrument.
     * POS_A_COMP_INDEX(index) is the absolute position of component
       'index'. POS_A_COMP_INDEX(mccompcurindex) is the same as
       POS_A_CURRENT_COMP. You may use POS_A_COMP_INDEX(mccompcurindex+1) to
       make, for instance, your component access the position of the next
       component (this is usefull for automatic targeting).
     * SCATTERED is non zero when previous component acted on neutron (let pass
       or scatter)

   Warning: programmers, do not use anymore the 'mccompcurname' when writing
   your components. rather use the 'NAME_CURRENT_COMP'.

   Other minor modifications
   #cleaned up non used variables in mcstas-r.c/h
   #tested and corrected components
        misc: Vitess_input/output: included Spin from Vitess. (vitess-lib.c/h)
          but can not be used as mcstas can not find vitess-lib.c/h. I included
          what was needed in SHARE sections. now works OK.
            Single_crystal (now can take lattice angles, forgot a %} at SHARE
            provide *.dat diffraction samples from Crystallographica
            Beamstop now is a merging of Beamstop_circular and
              Beamstop_rectangular (using default  values to select shape)
            Channeled_guide: now output an error in multichannel focusing mode.
            Chopper: determined default values to have lambda~4 AA. Can handle
              First_Chopper (parameter IsFirst)
            Fermi_Chopper : default values for transmission every ~2 AA
            Gravity_guide: limit loops to max of 1000 bounces for each
              components (to avoid endless loops)
            Mosaic_anisotropic: can take DM (d-spacing). default for graphite.
            Powder_filter (did not work at all, now can take lattice angles,
              also works as a sample, can take samples/*.dat diffraction files)
            Selector: default values for transmission at ~4 AA
            Slit: now is a merging of Slit and Circular_slit (using default
              values to select shape)
            Soller: can take transmission
            V_selector: default values for transmission at ~4 AA
            Source_gen: can handle all previous sources in one component (up to
              3 Maxwellians). Corrected homogeneity bug for illumination.
            Source_file: can read 'source' files from Vitess, text files (both
              90 bytes/neutron) and float binary  files (e.g, from Monitor_nD
              with options="list all, source binary" which is more compact in
              size, 48  bytes/neutron). Autorecognition of the format. The MCNP
              output is not fixed. Just tell MCNP  guys to output the float
              binary or text file.
   #other tested components:
        monitors: all
        optics: Bender, Curved_Monochromator, Filter, Filter_Graphite,
          Gravity_guide, Mon_2foc,
        Curved_Monochromator, Monochromator
   #not tested: Guide, He3_cell, Mirror, (should be ok ??!!)
   #moved to obsolete components:
        monitors: PSD_monitor_4PI_log.comp, PSD_bidim.comp, PSD_curved.comp,
        samples: Powder0.comp
            Beamstop_circular Beamstop_rectangular (gathered into Beamstop)
            First_Chopper (included in Chopper)
            Circular_slit (included in Slit)
   #perl scripts: mcplot (direct output -ps, -psc, -gif)

Changes in McStas v1.5, October, 10th, 2001

Modified components
      A corrected version of Arm.comp. For further information, see the emails by Ulrich
      Wildgruber and Stuart Rycroft. (Apr. 26, 2001)
      A corrected version of  Monitor_nD.comp. For further information, see the email by
      Emmanuel Farhi. (Apr. 26, 2001)
      A rewritten version of Gravity_guide.comp has been contributed by Emmanuel Farhi
      (see email). The component provided in the email works with McStas 1.4.2, but the official
      version of the component is not working with McStas 1.4.2 because support for this
      component has been added to the kernel. (Aug. 7, 2001)
      An updated version of Monitor_nD.comp has been contributed by Emmanuel Farhi (see
      first and second email). The new version of the component is not working with McStas
      1.4.2 because support for the component has been added to the kernel. (Aug. 8, 2001)
      Andrew Wildes and Emmanuel Farhi have detected an error when using focusing
      geometry in Channeled_guide. The slope of the channels is not computed corrected
      correctly, because the same left and right slopes are used in all channels. This has now
      been included properly in Gravity_guide, and it is recommended that this component is
      used. (Sep. 18, 2001)
      The handling of illumination in Source_flat, Source_div and Source_flat_lambda have
      been corrected. (Oct. 9, 2001)
  New components
      The He3_cell.comp has been contributed by Trefor Roberts. It models a cylindrical 3He
      spin filter cell. (Aug. 8, 2001)
      The Mon_2foc.comp has been contributed by Peter Link. It models a double bent
      monochromator with multiple slabs. (Aug. 9, 2001)
      The Bender.comp has been contributed by Philipp Bernhardt. It models a curved neutron
      guide. (Aug. 10, 2001)
      The Powder_filter.comp has been contributed by Ben Fortescue. It models a general
      box-shaped powder filter. (Aug. 16, 2001)
      The Source_Maxwell_3 component describes a source with three Maxwellian
      distributions. (Sep. 17, 2001)
      Various monitors have been added: EPSD_monitor, PSDcyl_monitor, PSDlin_monitor,
      TOF_cylPSD_monitor, TOFlog_mon. (Sep. 18, 2001)
          A minor error in TOF_cylPSD_monitor has been corrected. (Oct. 9, 2001)
      A new monitor TOFLambda_monitor has been added. (Oct. 9, 2001)
      A guide modeling waviness, Guide_wavy, has been added. (Oct. 9, 2001)
      A generic source, Source_gen, has been added. (Oct. 10, 2001)
  The signal handling system has been updated to handle a special case. The signal handling
  system will be documented in the manual of version 1.5. (Aug. 7, 2001)
  The representation of polarisation in McStas components and instruments is supposed to work
  as follows. Only components actually modifying the spin explicitly require the "POLARISATION
  PARAMETERS (sx,sy,sz)" line. An instrument handling polarisation may consist of  components
  both with and without this line; it will transform the spin vector correctly anyway. The
  "POLARISATION PARAMETERS (sx,sy,sz)" line is therefore removed from all official
  components not dealing with polarisation. The reason is that for instruments without polarisation
  some simulation time is gained by excluding the transformations of the spin vector. (Aug. 9,
  Some definitions have been added that can be used in coding components:
      NAME_CURRENT_COMP gives the name of the current component as a string. (Aug.
      16, 2001)
      POS_A_CURRENT_COMP gives the absolute position of the current component. A
      component of the vector is referred to as POS_A_CURRENT_COMP.i where i is x, y or z.
      (Aug. 16, 2001)
      ROT_A_CURRENT_COMP and  ROT_R_CURRENT_COMP give the orientation of the
      current component as rotation matrices (absolute orientation and the orientation relative to
      the previous component, respectively). A component of  a rotation matrice is referred to
      as  ROT_A_CURRENT_COMP[m][n], where m and n are 0, 1, or 2. (Aug. 16, 2001)
      POS_A_COMP(comp) gives the absolute position of the component with the name
      comp. Note that comp is not given as a string. A component of the vector is referred to as
      POS_A_COMP(comp).i where i is x, y or z. (Aug. 16, 2001)
      ROT_A_COMP(comp) and ROT_R_COMP(comp)  give the orientation of the
      component comp as rotation matrices (absolute orientation and the orientation relative to
      its previous component, respectively). Note that comp is not given as a string. A
      component of  a rotation matrice is referred to as  ROT_A_COMP(comp)[m][n], where
      m and n are 0, 1, or 2. (Aug. 16, 2001)

Changes in McStas v1.4.1, March 16, 2001

 - New components: ESS_moderator_long.comp and ESS_moderator_short.comp
   (by Kim Lefmann), Source_Maxwell (by Emmanuel Farhi). Gravity_guide.comp
   is included in the official version.
 - Some support for the calculation of correlation functions in the
   components Monitor_nD and PreMonitor_nD (by Emmanuel Farhi)
 - A signal handling system is included (by Emmanuel Farhi)
 - Misc. minor bug fixes
 - For more information:

Changes in McStas v1.4, July 28, 2000:

 - It is now possible to use arbitrary C expressions in the instrument
   definition, ie. to set rotations, component parameters, etc. Only
   works for SETTING parameters though, not DEFINITION parameters.
 - Experimental mcstas2vitess conversion program to automatically
   translate a McStas component into a VITESS module.
 - Option to clear the simulation output in mcgui.
 - Partial solution to the problem with name conflicts on component
 - Partial NeXus support implemented, but not yet functional.
 - Misc. minor bug fixes.

Changes in McStas v1.3, May 18, 2000:

 - New facility `McDoc' for documentation of components, with
   automatic extraction of documentation from comment headers in the
   source code.
 - The possibility in the graphical user interface `mcgui' to build
   instrument definitions using "point-and-click", based on McDoc.
 - Much improved `mcrun' front-end, which now replaces the old `gscan'
   front-end and interfaces with `mcplot'.
 - Optional component input parameters.
 - Instrument parameters may now also be of string type.
 - Improved Single_crystal component, now supports anisotropic mosaic,
   multiple scattering, extinction, absorbtion, and incoherent
 - New components Source_Optimizer and Monitor-nD, by Emmanuel Farhi.
 - Misc. minor bug fixes.

Changes in McStas v1.2, January 31, 2000:

 - New components (Single_crystal, Mosaic_simple, Source_adapt,
   Res_sample, ...).
 - New graphical user interface mcgui.
 - New command-line front-end mcrun with automatic compilation
 - New resolution function front-end mcresplot (experimental).
 - Better random number generator "Mersenne Twister".
 - Fix for problem with Digital Unix almost-ANSI compiler.
 - Misc. minor bug fixes.

Changes in McStas v1.1, March 31, 1999:

 - New components.
 - Much improved output file format, with new mcplot front-end to
   automatically plot the results of a simulation.
 - New MCDISPLAY sections in component definitions, and much improved
   mcdisplay front-end.
 - New kernel calls DETECTOR_OUT_[012]D(), mcget_ncount().
 - Improved error messages.
 - New --portable compiler option.
 - Various minor bug and compatibility fixes.
 - Preliminary support for polarised neutrons.
 - Quote special characters in strings in the generated C code.

Changes in McStas v1.0, October 26, 1998:

 - Initial release.

Last Modified: Wednesday, 24-Sep-2014 17:47:21 CEST
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