blob: ea41315990aebede04bf5aab748582b68e0edbd3 [file] [log] [blame]
// IWYU pragma: private
#include "./InternalHeaderCheck.h"
namespace Eigen {
namespace internal {
// TODO : move this to GivensQR once there's such a thing in Eigen
template <typename Scalar>
void r1mpyq(DenseIndex m, DenseIndex n, Scalar *a, const std::vector<JacobiRotation<Scalar> > &v_givens,
const std::vector<JacobiRotation<Scalar> > &w_givens) {
typedef DenseIndex Index;
/* apply the first set of givens rotations to a. */
for (Index j = n - 2; j >= 0; --j)
for (Index i = 0; i < m; ++i) {
Scalar temp = v_givens[j].c() * a[i + m * j] - v_givens[j].s() * a[i + m * (n - 1)];
a[i + m * (n - 1)] = v_givens[j].s() * a[i + m * j] + v_givens[j].c() * a[i + m * (n - 1)];
a[i + m * j] = temp;
}
/* apply the second set of givens rotations to a. */
for (Index j = 0; j < n - 1; ++j)
for (Index i = 0; i < m; ++i) {
Scalar temp = w_givens[j].c() * a[i + m * j] + w_givens[j].s() * a[i + m * (n - 1)];
a[i + m * (n - 1)] = -w_givens[j].s() * a[i + m * j] + w_givens[j].c() * a[i + m * (n - 1)];
a[i + m * j] = temp;
}
}
} // end namespace internal
} // end namespace Eigen