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/*
Copyright (C) 2018 arbguest
Copyright (C) 2018 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 "arb.h"
#include "arb_mat.h"
void
arb_mat_approx_solve_lu_precomp(arb_mat_t X, const slong * perm,
const arb_mat_t A, const arb_mat_t B, slong prec)
{
slong i, c, n, m;
n = arb_mat_nrows(X);
m = arb_mat_ncols(X);
if (X == B)
{
arb_ptr tmp = flint_malloc(sizeof(arb_struct) * n);
for (c = 0; c < m; c++)
{
for (i = 0; i < n; i++)
tmp[i] = *arb_mat_entry(B, perm[i], c);
for (i = 0; i < n; i++)
*arb_mat_entry(X, i, c) = tmp[i];
}
flint_free(tmp);
}
else
{
for (c = 0; c < m; c++)
{
for (i = 0; i < n; i++)
{
arb_set(arb_mat_entry(X, i, c),
arb_mat_entry(B, perm[i], c));
}
}
}
arb_mat_get_mid(X, X);
arb_mat_approx_solve_tril(X, A, X, 1, prec);
arb_mat_approx_solve_triu(X, A, X, 0, prec);
}