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Phase-2 structural pilots: IC context type, unified BC dispatcher, boundary module split#1555

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Phase-2 structural pilots: IC context type, unified BC dispatcher, boundary module split#1555
sbryngelson wants to merge 34 commits into
MFlowCode:masterfrom
sbryngelson:phase2-pilots

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Stacked on #1551#1552#1553 — this branch includes all three; its own content is the top 3 commits. First installment of the refactoring roadmap's Phase 2 (structural consolidation): three pilots, one per workstream, validating the patterns before the rest of the phase.

Summary

  1. Context derived type (pilot for state-bundling). pre_process's five module-level initial-condition arrays (q_prim_vf, q_cons_vf, q_T_sf, bc_type, patch_id_fp) bundle into one ic_context in m_derived_types — plain data, no methods, mixed-precision variant preserved. Other modules' signatures are untouched (they already received these as arguments). +2 net LOC; emitted-Fortran equivalence verified (zero executable-statement diffs after qualifying the references).

  2. Direction-unified BC dispatcher (pilot for de-triplication). s_populate_variables_buffers carried six near-identical x/y/z-beg/end blocks; they collapse into one parameterized s_populate_bc_direction(bc_dir, bc_loc, ...). −105 net LOC. Behavior preserved exactly per (direction, location) pair, including a subtlety the original encodes: only y-beg dispatches BC_AXIS and excludes it from qbmm extrapolation — y-end does not, and the unified guard reproduces that asymmetry. GPU directive census: six identical GPU_PARALLEL_LOOP shells become one (with one added private scalar); both backends, otherwise unchanged. The BC-code read is hoisted to a loop-private, and the bc_type edge is passed as an integer_field so the helper contains no constant direction subscripts (keeps case-optimized 1D builds compiling).

  3. Module split (pilot for giant-file decomposition). m_boundary_common.fpp (2,250 lines) splits into the dispatcher+lifecycle core (194 lines), m_boundary_primitives (the eight GPU_ROUTINE BC helpers + the device-resident bc_buffers), and m_boundary_io (capillary/IGR buffers, MPI types, restart read/write, grid buffers). Pure code motion: statement-multiset of the union equals the parent file per target; GPU-directive multiset md5-identical. The original module re-exports everything it used to own, so zero external callers change. One deliberate deviation from the plan is documented in-code: bc_buffers lives in m_boundary_primitives (its on-device consumer) rather than the core module, avoiding a use-cycle with the re-export.

Verification

  • Full golden suite (sharded, all ~590 cases) green on the complete stack.
  • Per-pilot independent review with reproduced evidence: emitted-.f90 statement-set equivalence (pilots 1, 3), six-way per-(dir,loc) behavior table and GPU-directive census (pilot 2), re-export resolution audit covering all 13 external consumer files (pilot 3).
  • Simulation grind times 0.99–1.00 vs parent across the benchmark suite (the dispatcher is hot-path; measured before the perf question was waived).

Notes for reviewers

  • All three pilots are strictly behavior-preserving; no golden files changed.
  • The patterns these pilots validate (context types for pre/post state, direction parameterization, seam-based file splits) are the templates for the remainder of Phase 2 (post-process contexts, m_riemann_solvers split) — feedback on the patterns here shapes those.

Sweeps bubble_model, avg_state, wave_speeds, recon_type, muscl_order, muscl_lim, int_comp, format, and precision (99 sites). Includes renaming legacy WENO_TYPE/MUSCL_TYPE comparisons to recon_type_weno/recon_type_muscl (same values) and two select-case labels in m_qbmm; WENO_TYPE/MUSCL_TYPE retirement is a follow-up.
Fypp resolves #:include at parse time, so generated_case_opt_decls.fpp is now emitted for every target (header-only stub outside simulation) and included unconditionally. Restores the dropped shear GPU_DECLARE (consumed in device kernels), restores the original nmom guard conditions in pre/post, and drops unused imports. The post-process beta_idx ordering change from the hoist is retained deliberately: it aligns post with simulation's writer layout (the parent ordering was inconsistent for bubbles_lagrange combined with mhd/elasticity/etc.).
Simulation declares nb in its own case-optimization block (excluded from generated decls), so the hoisted routine cannot reference it directly; pass it as an argument like nmom.
Drive s_mpi_bcast_user_inputs in all three m_mpi_proxy.fpp files from
generate_bcast_fpp(target) in fortran_gen.py. The generator emits case_dir,
class-(a) scalars (INT/LOG/REAL), FORTRAN_ARRAY_DIMS arrays, and the
fluid_pp / bub_pp / lag_params / chem_params struct-array loops. Manual
residues (bc_x/y/z members, domain bounds, m/n/p_glb, patch loops, etc.)
stay in each file. get_generated_files() grows from 12 to 15 entries.

Latent bug fixed: chem_wrt_Y (post, FORTRAN_ARRAY_DIMS dim=num_species)
was namelist-bound but never broadcast; consumed by s_save_data on all
ranks. Registry-driven generation closes it by construction.

Tuple-set equivalence: pre +n_start_old (dead param, harmless), post
+chem_wrt_Y only, sim exact identity.
bc_x/y/z are per-target declarations (the documented multi-variable-line exclusion), so their default assignments cannot live in m_global_parameters_common; the hoist had moved them and broke compilation. Restores the three BC default blocks to each executable after the s_assign_common_defaults call.
Verbatim motion only — no renames, reflows, or logic changes.

Section map (original line ranges → files):
  lines 129-331  compiler flags / GPU logic → cmake/GPU.cmake
  lines 107-461  FYPP_EXE discovery + HANDLE_SOURCES → cmake/Fypp.cmake
  lines 464-541  params codegen stamp + gen-file lists + custom command/target → cmake/ParamsCodegen.cmake
  lines 549-821  MFC_SETUP_TARGET function → cmake/MFCTargets.cmake

include() order in root CMakeLists.txt:
  1. cmake/GPU.cmake         (sets FYPP_GCOV_OPTS, NVHPC_USE_TWO_PASS_IPO, MFC_CUDA_CC)
  2. cmake/Fypp.cmake        (finds FYPP_EXE, defines HANDLE_SOURCES — needs FYPP_GCOV_OPTS)
  3. cmake/ParamsCodegen.cmake (sets _mfc_gen_files_* lists — must precede HANDLE_SOURCES calls)
  4. HANDLE_SOURCES calls    (in root — consume _mfc_gen_files_* and FYPP_EXE)
  5. cmake/MFCTargets.cmake  (defines MFC_SETUP_TARGET — needs NVHPC_USE_TWO_PASS_IPO)
  6. MFC_SETUP_TARGET calls  (in root — instantiate targets)
  7. docs section            (in root — unchanged)

Equivalence gate: cmake configure of -DMFC_PRE_PROCESS=ON -DMFC_MPI=OFF
-DCMAKE_BUILD_TYPE=Release BEFORE and AFTER, path-normalized diff of
CMakeCache.txt, Makefile, CMakeFiles/pre_process.dir/flags.make, and
CMakeFiles/pre_process.dir/build.make — all empty (identical).

A clean 3-target build rides the next scheduled gate.
…ludes

Delete the configure-time execute_process + stamp block from
cmake/ParamsCodegen.cmake (29 lines removed). The build-time
add_custom_command is now the sole mechanism that writes the 15
generated_*.fpp includes.

Cold-start proof (scratch build dir, no pre-existing includes):
- cmake configure succeeds with include/ absent
- make -n shows cmake_gen.py scheduled before all fypp steps
- make mfc_params_gen produces all 15 files across 3 target dirs
Incremental proof: touch toolchain/mfc/params/definitions.py ->
make -n schedules regeneration without reconfigure.

cmake_gen.py already calls path.parent.mkdir(parents=True,exist_ok=True)
so no file(MAKE_DIRECTORY) guards were added. find_package(Python3) is
kept in ParamsCodegen.cmake (the CMakeLists.txt one is in a docs block
that runs later). Full build+test rides the next gate.
The hardcoded fluid_pp emitter predated the MFlowCode#1545 merge and silently dropped K/nn/tau0/hb_m/mu_min/mu_max/mu_bulk and non_newtonian from the generated lists - a multi-rank regression for non-Newtonian runs relative to the manual lists it replaced. Emitted sets now verified member-identical to master's manual lists per target. Caught by automated PR review.
The named-constant retirement deleted the WENO/MUSCL block between two section headings and merged them into one nonsensical comment. Flagged by automated PR review on MFlowCode#1552.
…h dedup docs

NIB read num_ib_patches_max (2050000) but the patch_ib namelist array is dimensioned num_ib_patches_max_namelist (54000), so validation accepted indices that overflow the array. Also refreshes three doc passages made stale by the dedup. Both flagged by review.
Cray ftn rejects declare-target on use-associated names (ftn-1448 on Frontier gpu-omp): the dedup hoisted these declarations into the common module but left their GPU_DECLARE lines in simulation. Declares move to the declaring module; mixed lines split so locally-declared variables keep their declares in place. CPU-preprocessed output verified identical; declare-target scoping verified clean for both files under OpenMP emission.
fluid_pp%{mul0,ss,pv,gamma_v,M_v,mu_v,k_v,cp_v,D_v} and
lag_params%{T0,Thost,c0,rho0,x0} were removed from the Fortran derived
types by upstream MFlowCode#1085/MFlowCode#1093 but remained registered in the toolchain.
Setting any of them causes namelist read to abort with a misleading
'datatype mismatch' error.

Verified against src/common/m_derived_types.fpp:
- physical_parameters has: gamma, pi_inf, Re, cv, qv, qvp, G
- bubbles_lagrange_parameters has: solver_approach, cluster_type,
  pressure_corrector, smooth_type, heatTransfer_model, massTransfer_model,
  write_bubbles, write_bubbles_stats, nBubs_glb, epsilonb, charwidth, valmaxvoid

Also remove the now-dead PATTERNS entries in descriptions.py and update
the stale comments in fortran_gen.py (_emit_fluid_pp and _emit_lag_params).
Both emitters now walk the registry rather than hardcoding member lists.
bc_x/y/z%{vb1,vb2,vb3,ve1,ve2,ve3} are read from the namelist on rank 0
and consumed on all ranks by s_slip_wall/s_no_slip_wall in
src/common/m_boundary_common.fpp (~833-1155). These routines are compiled
into all three targets and are reached from pre_process (m_data_output,
m_perturbation) and post_process (m_start_up) code paths.

Without the broadcast, non-root ranks use uninitialised values for the
wall-velocity components, producing rank-dependent ghost cells for any
multi-rank wall-BC pre-process or post-process run. The sim residue has
always broadcast these; pre and post were missing them.

Add the matching broadcasts to both pre and post using the same nested
Fypp loop idiom as the simulation residue.
muscl_eps was excluded from broadcast generation via _BCAST_EXCLUDE on the
incorrect assumption that it is derived post-broadcast. The derivation
(in m_weno or m_muscl) only fires under f_is_default(muscl_eps), and
default values are assigned on rank 0 only. Every multi-rank MUSCL run
therefore had rank-divergent muscl_eps on non-root ranks. Remove it from
the exclusion set.

Tuple-set delta (var, mpi_type, count) vs. HEAD~:
  sim: +1 entry: (muscl_eps, mpi_p, 1)
  pre: no change
  post: no change

_emit_fluid_pp and _emit_lag_params now walk the registry instead of
maintaining hardcoded member lists. After Commit 1 deregistered the
dead members (mul0/ss/pv/gamma_v/M_v/mu_v/k_v/cp_v/D_v for fluid_pp;
T0/Thost/c0/rho0/x0 for lag_params), the registry now matches the
Fortran types exactly. Re(1) count=2 remains sim-only via an explicit
target check with a comment. G is walked as a regular REAL member.

Tests: 3 new tests added — muscl_eps now broadcast in sim, fluid_pp and
lag_params registry walks produce exactly the registered members minus
documented exclusions, dead members absent.
…idue broadcasts

pre_process sent the integer bc_x/y/z%beg/%end with mpi_p (an 8-byte real transfer over 4-byte integers - undefined behavior that happened to work by adjacency); simulation and post_process already used MPI_INTEGER. Also adds a test pinning the hand-written vb/ve and BC-code residue in pre/post so a merge conflict cannot silently drop them. Both from review.
Copilot AI review requested due to automatic review settings June 11, 2026 04:02

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@codecov

codecov Bot commented Jun 11, 2026

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Codecov Report

❌ Patch coverage is 57.69764% with 610 lines in your changes missing coverage. Please review.
✅ Project coverage is 60.94%. Comparing base (ac30c32) to head (f2fbd24).

Files with missing lines Patch % Lines
src/common/m_boundary_primitives.fpp 51.90% 171 Missing and 82 partials ⚠️
src/common/m_boundary_io.fpp 63.98% 119 Missing and 42 partials ⚠️
src/common/m_global_parameters_common.fpp 71.00% 31 Missing and 18 partials ⚠️
src/post_process/m_global_parameters.fpp 44.82% 23 Missing and 9 partials ⚠️
src/pre_process/m_global_parameters.fpp 53.70% 22 Missing and 3 partials ⚠️
src/post_process/m_data_output.fpp 5.00% 7 Missing and 12 partials ⚠️
src/simulation/m_global_parameters.fpp 63.26% 12 Missing and 6 partials ⚠️
src/simulation/m_riemann_solvers.fpp 25.00% 4 Missing and 5 partials ⚠️
src/common/m_mpi_common.fpp 0.00% 0 Missing and 7 partials ⚠️
src/simulation/m_qbmm.fpp 50.00% 0 Missing and 5 partials ⚠️
... and 12 more
Additional details and impacted files
@@            Coverage Diff             @@
##           master    #1555      +/-   ##
==========================================
- Coverage   61.17%   60.94%   -0.24%     
==========================================
  Files          74       77       +3     
  Lines       20313    19921     -392     
  Branches     2961     2924      -37     
==========================================
- Hits        12427    12141     -286     
+ Misses       5870     5804      -66     
+ Partials     2016     1976      -40     

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