Example instrument with adjustable ESS pulse-length.

[willend]

Free-form text area

Please describe what your PR is adding in terms of features or bugfixes:

Add example instrument that allows adjusting ESS pulse-length.

Ingredients:

• Input parameter named pulse_duration
• Checks for define ADJUSTABLE_ESS_PULSE
• DEPENDENCY “ -DADJUSTABLE_ESS_PULSE “ in the instrument file.

This PR constitutes a first implementation, improvements may come later.

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Development OS / boundary conditions

Please describe what OS you developed and tested your additions on, and if any special dependencies are required:

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PR Checklist for contributing to McStas/McXtrace

• My contribution includes patches to an existing component file

  • I have used the mcdoc utility and rendered a reasonable documentation page for the component (please attach as screenshot in comments!)
  • I have ensured that basic use of the component is OK (e.g. an instrument using it compiles?)
  • I have used the mctest utility to test one or more instruments making use of the component (please attach mcviewtest report as screenshot in comments)
  • I have used the mccode-clangformat tool to apply the standard McCode component indentation scheme
  • I have used the mcrun --c-lint "linter" and followed advice to remove most / all warnings that are raised

• My contribution includes a new instrument file

  • I have used the mcdoc utility and rendered a reasonable documentation page for the instrument (please attach as screenshot in comments!)
  • I have ensured that basic use of the instrument is OK (e.g. it compiles?)
  • ... and provided reasonable default parameters in that instrument that produce reasonable output
  • ... and maybe even added a %Example: line to describe expected behaviour
  • I have used the mcrun --c-lint "linter" and followed advice to remove most / all warnings that are raised
  • My new instrument is added within the examples hierarchy in a folder in the style of examples/ESS/New_stuff/New_stuff.instr
  • My new instrument has a new, unique filename, not clashing with existing example instruments
  • My new instrument requires a data/input file. If the datafile is specific for my instrument I have left it in the same example folder, but if general use I have placed it in the global data folder.

• My work touches / adds to the runtime lib code (.c,.h etc in multiple locations

  • I am have added reasoning and documentation for the change below
  • I am attaching test output in the comments

• My contribution contains something else

  • Explanation is added in free form text above or below the checklist

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[willend]

This error on windows / without conda is understood:

False positive. The ESS_butterfly.comp was touched, meaning that all instruments including that component were tested/compile attempted. (And currently MCPL is for some reason not functional in this limited importance workflow.)

[willend]

(mcstas-dev) CIN-969631:tmp peterwillendrup$ mctest --instr=butterfly                    
loading system configuration
Output of test will be placed in: .
ncount is: 1e6
Testing: 3.99.99

Finding instruments in: /Users/peterwillendrup/micromamba/envs/mcstas-dev/share/mcstas/resources/examples
Copying instruments to: ./mcstas-3.99.99_butterfly_1e6_Darwin_20260430_1846_04

Compiling instruments [seconds]...
ESS_butterfly_Ajustable_Pulse     :   3.39
ESS_butterfly_Guide_curved_test   :   3.51
ESS_butterfly_MCPL_test           :   3.59
ESS_butterfly_test                :   3.05
ESS_butterfly_tfocus_NOFOCUS_test :   3.10
ESS_butterfly_tfocus_test         :   3.11

Running tests / getting status...
ESS_butterfly_Ajustable_Pulse      :   1.97    [val: 272665000000.0 / 270000000000.0 = 101 %]
ESS_butterfly_Guide_curved_test    :   3.16    [val: 437995000000.0 / 440000000000.0 = 100 %]
ESS_butterfly_MCPL_test            :   NO TEST
ESS_butterfly_test                 :   1.94    [val: 272665000000.0 / 270000000000.0 = 101 %]
ESS_butterfly_tfocus_NOFOCUS_test  :   2.05    [val: 155625000.0 / 150000000.0 = 104 %]
ESS_butterfly_tfocus_test          :   1.30    [val: 148882000.0 / 150000000.0 = 99 %]
======================================
Overall test result:
SUCCESS
(mcstas-dev) CIN-