////////////////////////////////////////////////////////////////////////////////
//! Run a simple test
////////////////////////////////////////////////////////////////////////////////
bool runTest(unsigned int mat_size)
{
bool bResult = false;
std::vector<NumericT> diagonal(mat_size);
std::vector<NumericT> superdiagonal(mat_size);
std::vector<NumericT> eigenvalues_bisect(mat_size);
// -------------Initialize data-------------------
// Fill the diagonal and superdiagonal elements of the vector
initInputData(diagonal, superdiagonal, mat_size);
// -------Start the bisection algorithm------------
std::cout << "Start the bisection algorithm" << std::endl;
std::cout << "Matrix size: " << mat_size << std::endl;
bResult = viennacl::linalg::bisect(diagonal, superdiagonal, eigenvalues_bisect);
// Exit if an error occured during the execution of the algorithm
if (bResult == false)
return false;
// ---------------Check the results---------------
// The results of the bisection algorithm will be checked with the tql algorithm
// Initialize Data for tql1 algorithm
std::vector<NumericT> diagonal_tql(mat_size);
std::vector<NumericT> superdiagonal_tql(mat_size);
diagonal_tql = diagonal;
superdiagonal_tql = superdiagonal;
// Start the tql algorithm
std::cout << "Start the tql algorithm..." << std::endl;
viennacl::linalg::tql1<NumericT>(mat_size, diagonal_tql, superdiagonal_tql);
// Ensure that eigenvalues from tql1 algorithm are sorted in ascending order
std::sort(diagonal_tql.begin(), diagonal_tql.end());
// Compare the results from the bisection algorithm with the results
// from the tql algorithm.
std::cout << "Start comparison..." << std::endl;
for (unsigned int i = 0; i < mat_size; i++)
{
if (std::abs(diagonal_tql[i] - eigenvalues_bisect[i]) > EPS)
{
std::cout << std::setprecision(12) << diagonal_tql[i] << " != " << eigenvalues_bisect[i] << "\n";
return false;
}
}
/*
// ------------Print the results---------------
std::cout << "mat_size = " << mat_size << std::endl;
for (unsigned int i = 0; i < mat_size; ++i)
{
std::cout << "Eigenvalue " << i << ": \tbisect: " << std::setprecision(14) << eigenvalues_bisect[i] << "\ttql: " << diagonal_tql[i] << std::endl;
}
*/
return bResult;
}
/**
* The main program is now as follows:
**/
int main()
{
typedef float NumericT;
bool bResult = false;
unsigned int mat_size = 30;
/**
* Create STL-vectors holding the diagonal, the superdiagonal, and the computed eigenvalues:
**/
std::vector<NumericT> diagonal(mat_size);
std::vector<NumericT> superdiagonal(mat_size);
std::vector<NumericT> eigenvalues_bisect(mat_size);
/**
* Initialize the data with the helper routine defined earlier:
**/
initInputData(diagonal, superdiagonal, mat_size);
/**
* Run the bisection algorithm for the provided input
**/
std::cout << "Start the bisection algorithm" << std::endl;
bResult = viennacl::linalg::bisect(diagonal, superdiagonal, eigenvalues_bisect);
std::cout << std::endl << "---TUTORIAL COMPLETED---" << std::endl;
/**
* Uncomment the following code to also have the results printed:
**/
/*
// ------------Print the results---------------
std::cout << "mat_size = " << mat_size << std::endl;
for (unsigned int i = 0; i < mat_size; ++i)
{
std::cout << "Eigenvalue " << i << ": " << std::setprecision(8) << eigenvalues_bisect[i] << std::endl;
}
*/
exit(bResult == true ? EXIT_SUCCESS : EXIT_FAILURE);
}