LAPACK/cxx_main.cpp

This is an example of how to use the Teuchos::LAPACK class.

// @HEADER
// *****************************************************************************
//                    Teuchos: Common Tools Package
//
// Copyright 2004 NTESS and the Teuchos contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER
 
#include "Teuchos_LAPACK.hpp"
#include "Teuchos_SerialDenseMatrix.hpp"
#include "Teuchos_SerialDenseVector.hpp"
#include "Teuchos_Version.hpp"
 
int main(int argc, char* argv[])
{
  std::cout << Teuchos::Teuchos_Version() << std::endl << std::endl;
 
  // Creating an instance of the LAPACK class for double-precision routines looks like:
  Teuchos::LAPACK<int, double> lapack;
 
  // This instance provides the access to all the LAPACK routines.
  Teuchos::SerialDenseMatrix<int, double> My_Matrix(4,4);
  Teuchos::SerialDenseVector<int, double> My_Vector(4);
  My_Matrix.random();
  My_Vector.random();
 
  // Perform an LU factorization of this matrix.
  int ipiv[4], info;
  char TRANS = 'N';
  lapack.GETRF( 4, 4, My_Matrix.values(), My_Matrix.stride(), ipiv, &info );
 
  // Solve the linear system.
  lapack.GETRS( TRANS, 4, 1, My_Matrix.values(), My_Matrix.stride(),
    ipiv, My_Vector.values(), My_Vector.stride(), &info );
 
  // Print out the solution.
  std::cout << printMat(My_Vector) << std::endl;
 
  return 0;
}