Added example of iterative solver of linear systems with solver monitor.

Documentation/Examples/Solvers/Linear/CMakeLists.txt

 set( COMMON_EXAMPLES
    IterativeLinearSolverExample
+   IterativeLinearSolverWithMonitorExample
 )
 
 if( BUILD_CUDA )

Documentation/Examples/Solvers/Linear/IterativeLinearSolverWithMonitorExample.cpp

+#include <iostream>
+#include <memory>
+#include <chrono>
+#include <thread>
+#include <TNL/Algorithms/ParallelFor.h>
+#include <TNL/Matrices/SparseMatrix.h>
+#include <TNL/Devices/Host.h>
+#include <TNL/Devices/Cuda.h>
+#include <TNL/Solvers/Linear/Jacobi.h>
+
+template< typename Device >
+void iterativeLinearSolverExample()
+{
+   /***
+    * Set the following matrix (dots represent zero matrix elements):
+    *
+    *   /  2 -1    .    .    .   \
+    *   |  -1    2 -1    .    .   |
+    *   |  .    -1    2 -1.   .   |
+    *   |  .    .    -1    2 -1   |
+    *   \  .    .    .    -1    2 /
+    */
+   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;
+
+   /***
+    * Setup solver of the linear system
+    */
+   using LinearSolver = TNL::Solvers::Linear::Jacobi< MatrixType >;
+   LinearSolver solver;
+   solver.setMatrix( matrix_ptr );
+
+
+   /***
+    * Setup monitor of the iterative solver
+    */
+   using IterativeSolverMonitorType = TNL::Solvers::IterativeSolverMonitor< double, int >;
+   IterativeSolverMonitorType monitor;
+   TNL::Solvers::SolverMonitorThread t(monitor);
+   monitor.setRefreshRate(100);  // refresh rate = timeout in milliseconds
+   monitor.setVerbose(1);
+   monitor.setStage( "Jacobi stage:" );
+   TNL::Timer timer;
+   monitor.setTimer( timer );
+   solver.setSolverMonitor(monitor);
+   solver.setOmega( 0.001 );
+   //std::this_thread::sleep_for(std::chrono::milliseconds(3000)); // wait for 3 seconds to let the monitor doing something
+   timer.start();
+   solver.solve( b, x );
+   monitor.stopMainLoop();
+   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::Host >();
+
+#ifdef HAVE_CUDA
+   std::cout << "Solving linear system on CUDA device: " << std::endl;
+   iterativeLinearSolverExample< TNL::Devices::Cuda >();
+#endif
+}

Documentation/Examples/Solvers/Linear/IterativeLinearSolverWithMonitorExample.cu

+IterativeLinearSolverWithMonitorExample.cpp
\ No newline at end of file

Documentation/Tutorials/Solvers/Linear/tutorial_Linear_solvers.md

@@ -35,4 +35,12 @@ All iterative solvers for linear systems can be found in the namespace \ref TNL:
 
 The result looks as follows:
 
-\include IterativeLinearSolverExample.out
+\include IterativeLinearSolverExample.out
\ No newline at end of file
+
+
+
+\includelineno Solvers/Linear/IterativeLinearSolverWithMonitorExample.cpp
+
+The result looks as follows:
+
+\include IterativeLinearSolverWithMonitorExample.out
\ No newline at end of file