/*
Copyright (C) 2022 Fredrik Johansson
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "gr.h"
#include "gr_mat.h"
int
gr_mat_invert_cols(gr_mat_t mat, slong * perm, gr_ctx_t ctx)
{
if (gr_mat_is_empty(mat, ctx) == T_FALSE)
{
slong sz = ctx->sizeof_elem;
slong t, i;
slong c = mat->c;
slong k = mat->c / 2;
if (perm != NULL)
for (i = 0; i < k; i++)
FLINT_SWAP(slong, perm[i], perm[c - i - 1]);
for (t = 0; t < mat->r; t++)
for (i = 0; i < k; i++)
gr_swap(GR_MAT_ENTRY(mat, t, i, sz), GR_MAT_ENTRY(mat, t, c - i - 1, sz), ctx);
}
return GR_SUCCESS;
}