feat: Multiscale preconditioner #3779

klevzoff · 2025-08-17T04:54:13Z

Remaining items:

Fix multiscale in CUDA builds (compiles but crashes on run)
Fix documentation check
Rebaseline (new input nodes)

codecov · 2025-08-20T20:30:31Z

Codecov Report

❌ Patch coverage is 10.88235% with 2424 lines in your changes missing coverage. Please review.
✅ Project coverage is 57.24%. Comparing base (0cb3f1f) to head (f54a3d3).

Files with missing lines	Patch %	Lines
...onents/linearAlgebra/multiscale/mesh/MeshLevel.cpp	0.00%	319 Missing ⚠️
...ents/linearAlgebra/multiscale/msrsb/MsrsbUtils.cpp	0.00%	298 Missing ⚠️
...nearAlgebra/multiscale/msrsb/MsrsbLevelBuilder.cpp	0.00%	269 Missing ⚠️
...rAlgebra/multiscale/mesh/coarsening/Coarsening.cpp	0.00%	196 Missing ⚠️
...ebra/multiscale/msrsb/MsrsbLevelBuilderCoupled.cpp	0.00%	162 Missing ⚠️
...earAlgebra/multiscale/MultiscalePreconditioner.cpp	0.00%	156 Missing ⚠️
...onents/linearAlgebra/multiscale/mesh/MeshUtils.hpp	0.00%	154 Missing ⚠️
...nents/linearAlgebra/multiscale/mesh/DofManager.cpp	0.00%	127 Missing ⚠️
...rc/coreComponents/mesh/generators/VTKUtilities.cpp	16.19%	119 Missing ⚠️
...cale/mesh/coarsening/SemistructuredPartitioner.cpp	0.00%	105 Missing ⚠️
... and 29 more

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3779      +/-   ##
===========================================
- Coverage    58.42%   57.24%   -1.18%     
===========================================
  Files         1270     1299      +29     
  Lines       109177   111899    +2722     
===========================================
+ Hits         63786    64059     +273     
- Misses       45391    47840    +2449

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OmarDuran · 2025-08-20T21:15:40Z

@klevzoff I have to add the following fix f54a3d3. This was somehow lost in the rebasing process or part of an old implementation.

klevzoff · 2025-08-20T22:30:32Z

@OmarDuran disregard my previous (now deleted) comment, I just noticed that you pushed a commit with the fix.

OmarDuran

@klevzoff thank you for your effort in reviving this functionality.

victorapm · 2025-08-20T23:30:23Z

src/coreComponents/linearAlgebra/multiscale/msrsb/MsrsbLevelBuilderCoupled.cpp

+  if( params.multiscale.coarseType == LinearSolverParameters::PreconditionerType::direct )
+  {
+    params.solverType = LinearSolverParameters::SolverType::direct;
+    return LAI::createSolver( params );
+  }
+  else if( params.multiscale.coarseType == LinearSolverParameters::PreconditionerType::block )
+  {
+    GEOS_ERROR_IF_NE_MSG( m_builders.size(), 2, "More than 2 blocks are not supported yet" );
+    auto solver = std::make_unique< BlockPreconditioner< LAI > >( params.block );
+    for( integer i = 0; i < static_cast< integer >( m_builders.size() ); ++i )
+    {
+      geos::DofManager::SubComponent comp{ params.block.subParams[i]->multiscale.fieldName, { m_builders[i]->numComp(), true } };
+      solver->setupBlock( m_params.block.order[i], { comp }, m_builders[i]->makeCoarseSolver() );
+      solver->setProlongation( m_params.block.order[i], m_selectors[i] );
+    }
+    return solver;
+  }
+  else
+  {
+    params.preconditionerType = params.multiscale.coarseType;
+    return LAI::createPreconditioner( params );
+  }


just out of curiosity, how much work would it be to add hypre as an option here? So we could try a hybrid MsRSB+BoomerAMG @klevzoff @castelletto1

I can't remember if I tested this thoroughly, but I believe this should already work - line 318 will create BoomerAMG (via HyprePreconditioner) as a coarse-level solver, with parameters specified in the XML (amgXXX attributes). One can also limit the number of multiscale levels to 1 or 2 (maxLevels attribute) to leave a sufficiently large coarse problem for AMG to work on.

Nice, I'll take a look!

victorapm

Very nice to have this new capability

victorapm · 2025-08-21T01:55:19Z

src/coreComponents/linearAlgebra/multiscale/mesh/coarsening/SemistructuredPartitioner.cpp

+#ifdef GEOS_USE_METIS
+        metis::partition( graph.toViewConst(), m_params.graph.metis, m_numPart[0], areaPart.toView() );
+#else
+        GEOS_THROW( "Attempted to use METIS partition, but GEOSX is not built with METIS support.", InputError );


Suggested change

GEOS_THROW( "Attempted to use METIS partition, but GEOSX is not built with METIS support.", InputError );

GEOS_THROW( "Attempted to use METIS partition, but GEOS is not built with METIS support.", InputError );

victorapm · 2025-08-21T01:55:36Z

src/coreComponents/linearAlgebra/multiscale/mesh/coarsening/SemistructuredPartitioner.cpp

+#ifdef GEOS_USE_SCOTCH
+        scotch::partition( graph.toViewConst(), m_params.graph.scotch, m_numPart[0], areaPart.toView() );
+#else
+        GEOS_THROW( "Attempted to use Scotch partition, but GEOSX is not built with Scotch support.", InputError );


Suggested change

GEOS_THROW( "Attempted to use Scotch partition, but GEOSX is not built with Scotch support.", InputError );

GEOS_THROW( "Attempted to use Scotch partition, but GEOS is not built with Scotch support.", InputError );

victorapm · 2025-08-21T02:02:46Z

inputFiles/multiscalePreconditioner/solidMechanics/cube_msrsb.xml

+            preOrPost="both"
+            numSweeps="1"/>
+          <Coarsening
+            partitionType="cartesian"


Curiosity again... how does the method behave with the other types (semi-structured and graph)?

Copilot

Pull Request Overview

Adds a multiscale preconditioner capability to GEOS, introducing the Multiscale Restricted Smoothing Basis (MsRSB) method for solving linear systems with multi-level approaches. The feature expands linear solver options and mesh generation capabilities for improved performance on large-scale problems.

Adds complete multiscale preconditioner infrastructure with MsRSB implementation
Enhances VTK mesh generation with structured indexing support
Updates communication tools to support multiscale mesh operations

Reviewed Changes

Copilot reviewed 76 out of 77 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/docs/doxygen/GeosxConfig.hpp	Updates METIS library naming convention from GEOSX to GEOS
src/coreComponents/schema/schema.xsd*	Adds XML schema support for multiscale and InvariantImmiscibleFluid parameters
src/coreComponents/physicsSolvers/*.cpp/hpp	Integrates multiscale preconditioner into physics solvers
src/coreComponents/linearAlgebra/utilities/LinearSolverParameters.hpp	Adds comprehensive multiscale parameter structure
src/coreComponents/mesh/generators/VTK*.cpp/hpp	Enhances VTK mesh handling with structured indexing
src/coreComponents/mesh/mpiCommunications/*.cpp/hpp	Extends communication tools for object manager synchronization
src/coreComponents/linearAlgebra/multiscale/msrsb/*.cpp/hpp	New MsRSB level builder implementation

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Copilot · 2025-08-21T14:06:56Z