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#include "CrsMatrix.h"
#include "LanczosSolver.h"
#include "Matrix.h"
#include "Random48.h" // <--- is this thread safe?
int main(int argc, char* argv[])
{
typedef double RealType;
typedef std::complex<double> ComplexType;
typedef PsimagLite::ParametersForSolver<double> SolverParametersType;
typedef PsimagLite::Vector<ComplexType>::Type VectorComplexType;
typedef PsimagLite::Vector<RealType>::Type VectorRealType;
if (argc != 2) {
std::cout << "USAGE: " << argv[0] << " excited\n";
return 1;
}
SizeType excited = atoi(argv[1]);
SizeType n = 4;
PsimagLite::Matrix<ComplexType> m(n, n);
// fill m
m(1, 2) = -0.5;
m(2, 1) = PsimagLite::conj(m(1, 2));
m(0, 0) = m(3, 3) = -0.25;
m(1, 1) = m(2, 2) = 0.25;
std::cout << "matrix\n"
<< m << "\n";
PsimagLite::CrsMatrix<ComplexType> msparse(m);
SolverParametersType params;
params.lotaMemory = true;
params.tolerance = -1;
params.options = "reortho";
PsimagLite::LanczosSolver<SolverParametersType,
PsimagLite::CrsMatrix<ComplexType>,
VectorComplexType>
lanczosSolver(msparse, params);
PsimagLite::Random48<double> myrng(time(0));
VectorComplexType initialV(n, 0.0);
for (SizeType i = 0; i < n; ++i)
initialV[i] = myrng() - 0.5;
double e1 = 0;
VectorComplexType z1(n, 0.0);
lanczosSolver.computeOneState(e1, z1, initialV, excited);
std::cout << "energy1=" << e1 << "\n";
std::cout << z1 << "\n";
VectorRealType eigs(m.rows());
PsimagLite::diag(m, eigs, 'V');
for (SizeType i = 0; i < m.rows(); i++) {
std::cerr << "eigs[" << i << "]=" << eigs[i] << "\n";
}
VectorRealType zeig(n, 0.0);
for (SizeType i = 0; i < m.rows(); i++) {
zeig[i] = PsimagLite::real(m(i, 0));
}
std::cout << m << "\n";
}
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