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1 Commits (5f659ffba2e04a55314c2a676f711cd7ff366013)

Author SHA1 Message Date
Stack-1 acdd2e9eb5 [ADD] Nested (MATNEST-style) block matrix support and tests
Add a block-structured distributed operator that presents itself to Krylov
solvers and preconditioners as a single ordinary distributed matrix (the
PSBLAS analogue of PETSc MATNEST), targeting saddle-point systems
M = [[A, B^T], [B, 0]] with possibly rectangular sub-blocks.

Library (base/modules):
- psb_desc_nest_mod, psb_d_nest_mat_mod: grid of per-field descriptors and
  per-block sparse storage.
- psb_d_nest_base_mat_mod: psb_d_nest_base_mat, the operator extending
  psb_d_base_sparse_mat (local csmv, free, field-split hooks for a future
  block preconditioner).
- psb_cd_nest_tools_mod / psb_d_nest_tools_mod: composed global descriptor
  with union halo (psb_cd_nest_compose) and rectangular local block builder
  (psb_d_nest_rect_block), plus the per-block assembly wrappers.
- psb_d_nest_builder_mod: psb_d_nest_matrix, the user frontend with the
  init/ins/asb/free pattern hiding all descriptor/halo/compose/setup
  boilerplate.
- psb_d_nest_mod: umbrella module (use psb_d_nest_mod).

Remove the earlier bespoke per-block prototype (comm/psblas/vect modules and
the pde_nest_psblas test) superseded by the single MATNEST design.

Tests (test/nested): glob (square operator vs monolithic CSR oracle), rect
(genuinely rectangular blocks), cg (low-level path, ill-conditioned SPD
red-black Laplacian solved with standard CG), builder (same solve via the
utility), plus a README describing the design and usage. All pass serially
and in parallel, with results invariant to the process count.

Build hooks updated (autotools Makefiles + CMakeLists); the nested tests are
relocated out of test/pdegen into test/nested.

Author: Simone Staccone (Stack-1)
2 weeks ago