From 00103113c71bc68bc0e53c014f95dfb0c02d4300 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=C3=A1=C5=A1=20Oberhuber?= <oberhuber.tomas@gmail.com>
Date: Thu, 30 Dec 2021 13:09:22 +0100
Subject: [PATCH] Added example on getLinearSolver and getPreconditioner.
---
.../Examples/Solvers/Linear/CMakeLists.txt | 1 +
...iveLinearSolverWithRuntimeTypesExample.cpp | 84 +++++++++++++++++++
...tiveLinearSolverWithRuntimeTypesExample.cu | 1 +
3 files changed, 86 insertions(+)
create mode 100644 Documentation/Examples/Solvers/Linear/IterativeLinearSolverWithRuntimeTypesExample.cpp
create mode 120000 Documentation/Examples/Solvers/Linear/IterativeLinearSolverWithRuntimeTypesExample.cu
diff --git a/Documentation/Examples/Solvers/Linear/CMakeLists.txt b/Documentation/Examples/Solvers/Linear/CMakeLists.txt
index 0d2354617c..97c77e7317 100644
--- a/Documentation/Examples/Solvers/Linear/CMakeLists.txt
+++ b/Documentation/Examples/Solvers/Linear/CMakeLists.txt
@@ -3,6 +3,7 @@ set( COMMON_EXAMPLES
IterativeLinearSolverWithMonitorExample
IterativeLinearSolverWithTimerExample
IterativeLinearSolverWithPreconditionerExample
+ IterativeLinearSolverWithRuntimeTypesExample
)
if( BUILD_CUDA )
diff --git a/Documentation/Examples/Solvers/Linear/IterativeLinearSolverWithRuntimeTypesExample.cpp b/Documentation/Examples/Solvers/Linear/IterativeLinearSolverWithRuntimeTypesExample.cpp
new file mode 100644
index 0000000000..cbe7707cfe
--- /dev/null
+++ b/Documentation/Examples/Solvers/Linear/IterativeLinearSolverWithRuntimeTypesExample.cpp
@@ -0,0 +1,84 @@
+#include <iostream>
+#include <memory>
+#include <TNL/Algorithms/ParallelFor.h>
+#include <TNL/Matrices/SparseMatrix.h>
+#include <TNL/Devices/Host.h>
+#include <TNL/Devices/Cuda.h>
+#include <TNL/Solvers/LinearSolverTypeResolver.h>
+
+template< typename Device >
+void iterativeLinearSolverExample()
+{
+ /***
+ * Set the following matrix (dots represent zero matrix elements):
+ *
+ * / 2.5 -1 . . . \
+ * | -1 2.5 -1 . . |
+ * | . -1 2.5 -1. . |
+ * | . . -1 2.5 -1 |
+ * \ . . . -1 2.5 /
+ */
+ using MatrixType = TNL::Matrices::SparseMatrix< double, Device >;
+ using Vector = TNL::Containers::Vector< double, Device >;
+ const int size( 5 );
+ auto matrix_ptr = std::make_shared< MatrixType >();
+ matrix_ptr->setDimensions( size, size );
+ matrix_ptr->setRowCapacities( Vector( { 2, 3, 3, 3, 2 } ) );
+
+ auto f = [=] __cuda_callable__ ( typename MatrixType::RowView& row ) mutable {
+ const int rowIdx = row.getRowIndex();
+ if( rowIdx == 0 )
+ {
+ row.setElement( 0, rowIdx, 2.5 ); // diagonal element
+ row.setElement( 1, rowIdx+1, -1 ); // element above the diagonal
+ }
+ else if( rowIdx == size - 1 )
+ {
+ row.setElement( 0, rowIdx-1, -1.0 ); // element below the diagonal
+ row.setElement( 1, rowIdx, 2.5 ); // diagonal element
+ }
+ else
+ {
+ row.setElement( 0, rowIdx-1, -1.0 ); // element below the diagonal
+ row.setElement( 1, rowIdx, 2.5 ); // diagonal element
+ row.setElement( 2, rowIdx+1, -1.0 ); // element above the diagonal
+ }
+ };
+
+ /***
+ * Set the matrix elements.
+ */
+ matrix_ptr->forAllRows( f );
+ std::cout << *matrix_ptr << std::endl;
+
+ /***
+ * Set the right-hand side vector.
+ */
+ Vector x( size, 1.0 );
+ Vector b( size );
+ matrix_ptr->vectorProduct( x, b );
+ x = 0.0;
+ std::cout << "Vector b = " << b << std::endl;
+
+ /***
+ * Solve the linear system using diagonal (Jacobi) preconditioner.
+ */
+ auto solver_ptr = TNL::Solvers::getLinearSolver< MatrixType >( "tfqmr" );
+ auto preconditioner_ptr = TNL::Solvers::getPreconditioner< MatrixType >( "diagonal");
+ preconditioner_ptr->update( matrix_ptr );
+ solver_ptr->setMatrix( matrix_ptr );
+ solver_ptr->setPreconditioner( preconditioner_ptr );
+ solver_ptr->solve( b, x );
+ std::cout << "Vector x = " << x << std::endl;
+}
+
+int main( int argc, char* argv[] )
+{
+ std::cout << "Solving linear system on host: " << std::endl;
+ iterativeLinearSolverExample< TNL::Devices::Sequential >();
+
+#ifdef HAVE_CUDA
+ std::cout << "Solving linear system on CUDA device: " << std::endl;
+ iterativeLinearSolverExample< TNL::Devices::Cuda >();
+#endif
+}
diff --git a/Documentation/Examples/Solvers/Linear/IterativeLinearSolverWithRuntimeTypesExample.cu b/Documentation/Examples/Solvers/Linear/IterativeLinearSolverWithRuntimeTypesExample.cu
new file mode 120000
index 0000000000..ab40ffd370
--- /dev/null
+++ b/Documentation/Examples/Solvers/Linear/IterativeLinearSolverWithRuntimeTypesExample.cu
@@ -0,0 +1 @@
+IterativeLinearSolverWithRuntimeTypesExample.cpp
\ No newline at end of file
--
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