This directory contains the reproducible helper used for the OPALX gamma-gamma benchmarks.

The public CAIN source tree used here is https://github.com/cfruhling2/CAIN.

From this directory:

This will:

• remove any existing local CAIN-src/ and CAIN-build/ trees

• clone a fresh CAIN checkout

• apply the local portability patch set

• compile the cain executable

To rebuild without recloning:

A small CMake wrapper is provided for convenience:

• CAIN-src/: local source checkout

• CAIN-build/: local object/module/build directory

• CAIN-build/cain: compiled executable

Both generated directories are ignored by git.

For the current macOS / gfortran workflow, the helper applies three source patches before compilation:

• src/evufnchar.f: WRITE(TEXT,'(I)') → WRITE(TEXT,'(I0)')

• src/transport.f: WRITE(MAGNAM,'(I)') → WRITE(MAGNAM,'(I0)')

• src/lsrrdfl.f: replace the end-of-line marker definition with a portable CHAR(10) / CHAR(0) form

The helper handles both upstream lsrrdfl.f variants seen so far:

• PARAMETER (EOR=…​, EOF=…​)

• CHARACTER*1 EOR/Z'0A'/,EOF/Z'00'/

The helper currently builds with:

This directory is intentionally benchmark-oriented. It is not trying to provide an upstream-quality CAIN packaging layer; it only captures the exact clone, patch, and compile workflow used to generate the OPALX reference benchmarks.