update documentation for LoadMcStas

[Anders Markvardsen]

Update doc for LoadMcStas with Torben Nielsen's text:

/*WIKI* 

* Reads a McStas Nexus file into a Mantid WorkspaceGroup with a user-supplied name. Data generated by McStas monitor components are stored in workspaces of type Workspace2D or Event.

* LoadMcStas replaces LoadMcStasEventNexus. LoadMcStas can be used for reading McStas 2.1 histogram and event data. LoadMcStasNexus can be used for reading McStas 2.0 histogram data. 



===McStas compiling and running===
McStas 2.1 event data and the corresponding IDF for Mantid are generated as follows using these commands from an xterm:

* Compile McStas instrument code
** mcstas templateSANS_Mantid.instr --trace

* Compile c code
** gcc -o templateSANS_Mantid.out templateSANS_Mantid.c -lm -DUSE_NEXUS -lNeXus

* Generate IDF
** mcdisplay templateSANS_Mantid.instr --format=Mantid -n0

* Run simulation
** ./templateSANS_Mantid.out --format=Nexus 

The templateSANS_Mantid.instr file used in the above example can be found in  McStas neutron suite.


===McStas event data conventions===
For McStas to auto generate an IDF the McStas instrument file must obey:

* McStas instrument file name and the McStas defined name of the instrument must be the same
** E.g. templateSANS_Mantid.instr and “DEFINE INSTRUMENT templateSANS_Mantid(…. )” 

* In the McStas instrument file the source must be named “souceMantid”
** E.g. "COMPONENT sourceMantid = Source_simple(…. )"

* In the McStas instrument file the sample must be named “sampleMantid”
** E.g. "COMPONENT sampleMantid = Sans_spheres(…. )"


* In the McStas instrument file the event monitors must be named “nD_Mantid_#”
** E.g. "COMPONENT nD_Mantid_1 = Monitor_nD(…. )" 

The McStas component monitor_nD must be called with the argument: options ="mantid square x limits=[-0.2 0.2] bins=128 y limits=[-0.2 0.2] bins=128, neutron pixel t, list all neutrons".  Number of bins and limits can be chosen freely.

 
===Tested versions===
The new features added to McStas has been tested on the following platforms:

* Linux
* Mac
**Use either the Intel or gcc 4.8 compiler. Simulations using Nexus format and event data does not work using the Clang compiler.


===References===
For more information about McStas and its general usage for simulating neutron scattering instruments and experiments visit the McStas homepage http://www.mcstas.org.

*WIKI*/

[Anders Markvardsen]

Update to doc for loadmcstas. re #9686

provided by Torben and translated to rst format

Changeset: b555e780644291fb16d23cd85e75220edd5e665d

[Anders Markvardsen]

To tester:

Check that Torben WIKI updated text have been translated OK to LoadMcStas-v1.rst

[Michael Reuter]

The page is producing the following ​warnings. Also, the double-dash flags are rendered as single dashes. It looks the content has been transferred over correctly.

[Anders Markvardsen]

using fixed space literal instead of bold. re #9686

Changeset: f846c7e0e2591114e9a637ab9fe0b234fcb0635f

[Anders Markvardsen]

Tx to Michael for spotting missed warning.

Warning appear to be cleared in ​http://builds.mantidproject.org/job/develop_clean/167/warnings2Result/NORMAL/package.-1966826692/

To tester: see comment 4

[Karl Palmen]

Modify description so that Torben Nielsen's test is displayed as is and unwanted bolding is removed.

[Karl Palmen]

The rst file seems to be good translation, but still needs a usage example.

Please create a ticket for the usage example, if one does not already exist.

[Karl Palmen]

Merge remote-tracking branch 'origin/feature/9686_mcstas_doc_update'

Full changeset: ​2ebad7dfb3f3af55a1becc87996a993cef7a977e

[Nick Draper]

comment post to wrong ticket

[Stuart Campbell]

This ticket has been transferred to github issue ​10528