mirror of
https://github.com/vale981/arb
synced 2025-03-05 09:21:38 -05:00
55 lines
1.3 KiB
C
55 lines
1.3 KiB
C
/*
|
|
Copyright (C) 2018 Fredrik Johansson
|
|
|
|
This file is part of Arb.
|
|
|
|
Arb 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 2.1 of the License, or
|
|
(at your option) any later version. See <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include "arb_mat.h"
|
|
|
|
void
|
|
_arb_mat_diag_prod(arb_t res, const arb_mat_t A, slong a, slong b, slong prec)
|
|
{
|
|
if (b - a == 0)
|
|
{
|
|
arb_one(res);
|
|
}
|
|
else if (b - a == 1)
|
|
{
|
|
arb_set_round(res, arb_mat_entry(A, a, a), prec);
|
|
}
|
|
else
|
|
{
|
|
slong i;
|
|
|
|
arb_mul(res, arb_mat_entry(A, a, a), arb_mat_entry(A, a + 1, a + 1), prec);
|
|
for (i = a + 2; i < b; i++)
|
|
arb_mul(res, res, arb_mat_entry(A, i, i), prec);
|
|
|
|
/* no advantage? */
|
|
|
|
/*
|
|
arb_t t;
|
|
arb_init(t);
|
|
_arb_mat_diag_prod(t, A, a, a + (b - a) / 2, prec);
|
|
_arb_mat_diag_prod(res, A, a + (b - a) / 2, b, prec);
|
|
arb_mul(res, res, t, prec);
|
|
arb_clear(t);
|
|
*/
|
|
}
|
|
}
|
|
|
|
void
|
|
arb_mat_diag_prod(arb_t res, const arb_mat_t A, slong prec)
|
|
{
|
|
slong m, n;
|
|
|
|
m = arb_mat_nrows(A);
|
|
n = arb_mat_nrows(A);
|
|
|
|
_arb_mat_diag_prod(res, A, 0, FLINT_MIN(m, n), prec);
|
|
}
|