inv.cpp

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#ifndef _MSC_VER
#  include <itpp/config.h>
#else
#  include <itpp/config_msvc.h>
#endif
 
#if defined(HAVE_LAPACK)
#  include <itpp/base/algebra/lapack.h>
#endif
 
#include <itpp/base/algebra/inv.h>
 
 
namespace itpp
{
 
#if defined(HAVE_LAPACK)
 
bool inv(const mat &X, mat &Y)
{
  it_assert_debug(X.rows() == X.cols(), "inv: matrix is not square");
 
  int m = X.rows(), info, lwork;
  lwork = m; // may be choosen better
 
  ivec p(m);
  Y = X;
  vec work(lwork);
 
  dgetrf_(&m, &m, Y._data(), &m, p._data(), &info); // LU-factorization
  if (info != 0)
    return false;
 
  dgetri_(&m, Y._data(), &m, p._data(), work._data(), &lwork, &info);
  return (info == 0);
}
 
bool inv(const cmat &X, cmat &Y)
{
  it_assert_debug(X.rows() == X.cols(), "inv: matrix is not square");
 
  int m = X.rows(), info, lwork;
  lwork = m; // may be choosen better
 
  ivec p(m);
  Y = X;
  cvec work(lwork);
 
  zgetrf_(&m, &m, Y._data(), &m, p._data(), &info); // LU-factorization
  if (info != 0)
    return false;
 
  zgetri_(&m, Y._data(), &m, p._data(), work._data(), &lwork, &info);
  return (info == 0);
}
 
#else
 
bool inv(const mat &X, mat &Y)
{
  it_error("LAPACK library is needed to use inv() function");
  return false;
}
 
bool inv(const cmat &X, cmat &Y)
{
  it_error("LAPACK library is needed to use inv() function");
  return false;
}
 
#endif // HAVE_LAPACK
 
cmat inv(const cmat &X)
{
  cmat Y;
  inv(X, Y);
  return Y;
}
 
 
mat inv(const mat &X)
{
  mat Y;
  inv(X, Y);
  return Y;
}
 
} // namespace itpp