// tutorial0_lapack.cc
#include <exception>

#include "magma_lapack.h"

// -----------------------------------------------------------------------------
// generates random n-by-n A and n-by-nrhs X in CPU host memory
void generate_problem( int n, int nrhs,
                       double* A, int lda,
                       double* X, int ldx )
{
    for (int j = 0; j < n; ++j) {
        for (int i = 0; i < n; ++i) {
            A[ i + j*lda ] = rand() / double(RAND_MAX);
        }
    }
    for (int j = 0; j < nrhs; ++j) {
        for (int i = 0; i < n; ++i) {
            X[ i + j*ldx ] = rand() / double(RAND_MAX);
        }
    }
}

// -----------------------------------------------------------------------------
// CPU interface: input & output matrices A and X in CPU host memory
int main( int argc, char** argv )
{
    int n = 100, nrhs = 10;
    int lda = n, ldx = n;
    double *A = new double[ lda*n ];
    double *X = new double[ ldx*nrhs ];
    int* ipiv = new int[ n ];

    // ... fill in A and X with your data
    // A[ i + j*lda ] = A_ij
    // X[ i + j*ldx ] = X_ij
    generate_problem( n, nrhs, A, lda, X, ldx );

    // solve A X = B where B is in X
    int info;
    lapackf77_dgesv( &n, &nrhs,
                     A, &lda, ipiv,
                     X, &ldx, &info );
    if (info != 0) {
        throw std::exception();
    }

    // ... use result in X

    delete[] A;
    delete[] X;
    delete[] ipiv;
}