hecmw_precond_SAAMG_aggregate.f90 File Reference

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Modules
module	hecmw_precond_saamg_aggregate
	Smoothed Aggregation AMG preconditioner : node graph + aggregation.

Functions/Subroutines
subroutine, public	hecmw_precond_saamg_aggregate::hecmw_saamg_build_nodegraph (A, g, theta)
	Build the node graph from the block-CSR operator A. With theta (optional) > 0, apply a strength-of-connection filter: an off-diagonal node-block (I,J) is an edge only if its Frobenius norm is strong relative to the diagonal blocks, ||A_IJ||_F >= theta * sqrt(||A_II||_F * ||A_JJ||_F). theta absent or <= 0 reproduces the structural graph (every nonzero block is an edge), matching the original theta=0 behavior. More...
subroutine, public	hecmw_precond_saamg_aggregate::hecmw_saamg_nodegraph_free (g)
subroutine, public	hecmw_precond_saamg_aggregate::hecmw_saamg_write_vtk (fname, coord, nnode, aggr)
	Write a legacy-VTK point cloud colored by aggregate id (ParaView diagnostic). coord is (x,y,z) interleaved, length 3*nnode; aggr(i) in 0..naggr (0=excluded). More...
subroutine, public	hecmw_precond_saamg_aggregate::hecmw_saamg_aggregate (g, min_size, max_size, aggr, naggr, order_mode, gid)
	Vanek 3-phase aggregation + min-size forced merge. aggr(1:n): 1..naggr for aggregated nodes, 0 for excluded nodes. order_mode (optional): phase-1 seed-scan ordering. Phase 1 builds a distance-2 maximal independent set of seeds – the only freedom is WHICH admissible seed is taken first, and that decides the aggregate shapes: 0/absent = natural node order (legacy; kept as the no-argument default so the standalone harness stays bit-stable), 1 = BFS (graph) order (the production default via prmagg_order: contiguous tiling -> uniform aggregates, much better on badly numbered meshes), 2 = hash order of gid (deterministic pseudo-random; with global ids the seed priority is partition-independent), 3 = min-degree first, 4 = max-degree first. gid: node ids for mode 2. More...