Fix Fortran Wrapper Parameter Passing Bug in barrier and forget Functions

[kellih]

Problem:
Fortran wrapper interfaces for barrier_* and forget_* functions incorrectly used the value attribute on scalar parameters (time values and reset flags), causing segmentation faults when called from Fortran code. The C++ implementation expects pointers (double *t, int *reset_log), but Fortran's value attribute passes by-value instead of by-reference.

Additional bug uncovered by commit 3ffd697 in CMakeLists.txt where MPI REQUIRED was not included for Fortran wrapper.

Scope:
Affects 90 function interfaces across all three spatial dimensions:

• 1D wrapper: 10 barrier + 20 forget functions
• 2D wrapper: 10 barrier + 20 forget functions
• 3D wrapper: 10 barrier + 20 forget functions

Changes Made:

1. Fortran Wrapper Fixes (wrappers/Fortran/)

• mui_f_wrapper_1d.f90 (lines 13865-14072): Fixed all 30 functions
• mui_f_wrapper_2d.f90 (lines 14228-14440): Fixed all 30 functions
• mui_f_wrapper_3d.f90 (lines 14427-14640): Fixed all 30 functions
• Removed , value attribute from scalar real and integer parameters
• Kept value attribute on type(c_ptr) parameters (correct usage)

2. CMake Build Configuration (CMakeLists.txt)

• Added find_package(MPI REQUIRED) for Fortran wrapper (lines 106-111)

3. Enhanced Unit Tests (wrappers/Fortran/)

• unit_test.f90: Added barrier calls after commit and forget calls after fetch for 1D, 2D, and 3D interfaces
• unit_test_multi.f90: Added barrier/forget loops for all dimensions in multi-interface test
• Tests validate proper parameter passing through actual MUI workflow

4. Testing:

• All fixes validated to eliminate segfaults in development code
• Unit tests successfully exercise barrier and forget functions across all dimensions

Backward Compatibility:
No API changes - this is a pure bug fix correcting the ABI between Fortran and C++.

Resolves issue #115

[Wendi-L]

Hi @kellih,

Many thanks for your contribution! Overall, the PR looks good to me.

I just have one comment regarding the removal of the following lines in ‎src/mui.h:

• #include "samplers/temporal/temporal_sampler_linear.h" (line 68)
• DECLARE_SAMPLER_0ARG(temporal_sampler_linear,SUFFIX,config_##SUFFIX); (line 123)
• DECLARE_SAMPLER_0ARG(temporal_sampler_linear,SUFFIX,CONFIG); (line 165)

These should be kept. I believe the temporal_sampler_linear implementation was still being merged when you created this PR, so removing these lines was understandable at that time. This piece of work on temporal_sampler_linear has now been completed, and these declarations are required.

If you could revert these changes, I will carry out a final round of testing and then proceed with the merge.

Thanks again for your contribution!

[Wendi-L]

Please keep this include. temporal_sampler_linear has now been merged and is required.

[Wendi-L]

Please keep this declaration. temporal_sampler_linear is now part of the main codebase.

[Wendi-L]

Please keep this declaration. temporal_sampler_linear is now part of the main codebase.

[Wendi-L]

I don't think temporal_sampler_gauss_adaptive is a part of the code base. Suggest removing this include