mirror of
https://github.com/vale981/arb
synced 2025-03-06 01:41:39 -05:00
127 lines
3.3 KiB
C
127 lines
3.3 KiB
C
/*
|
|
Copyright (C) 2018 arbguest
|
|
|
|
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 "acb_mat.h"
|
|
|
|
static void
|
|
_acb_approx_mul(acb_t res, const acb_t x, const acb_t y, slong prec)
|
|
{
|
|
arf_complex_mul(arb_midref(acb_realref(res)), arb_midref(acb_imagref(res)),
|
|
arb_midref(acb_realref(x)), arb_midref(acb_imagref(x)),
|
|
arb_midref(acb_realref(y)), arb_midref(acb_imagref(y)), prec, ARB_RND);
|
|
}
|
|
|
|
static void
|
|
_acb_approx_submul(acb_t z, const acb_t x, const acb_t y, acb_t t, slong prec)
|
|
{
|
|
_acb_approx_mul(t, x, y, prec);
|
|
|
|
arf_sub(arb_midref(acb_realref(z)),
|
|
arb_midref(acb_realref(z)),
|
|
arb_midref(acb_realref(t)), prec, ARB_RND);
|
|
arf_sub(arb_midref(acb_imagref(z)),
|
|
arb_midref(acb_imagref(z)),
|
|
arb_midref(acb_imagref(t)), prec, ARB_RND);
|
|
}
|
|
|
|
/* note: the tmp variable t should have zero radius */
|
|
static void
|
|
_acb_approx_div(acb_t z, const acb_t x, const acb_t y, acb_t t, slong prec)
|
|
{
|
|
arf_set(arb_midref(acb_realref(t)), arb_midref(acb_realref(y)));
|
|
arf_set(arb_midref(acb_imagref(t)), arb_midref(acb_imagref(y)));
|
|
|
|
acb_inv(t, t, prec);
|
|
|
|
mag_zero(arb_radref(acb_realref(t)));
|
|
mag_zero(arb_radref(acb_imagref(t)));
|
|
|
|
_acb_approx_mul(z, x, t, prec);
|
|
}
|
|
|
|
void
|
|
acb_mat_approx_solve_lu_precomp(acb_mat_t X, const slong * perm,
|
|
const acb_mat_t A, const acb_mat_t B, slong prec)
|
|
{
|
|
acb_t t;
|
|
slong i, j, c, n, m;
|
|
|
|
n = acb_mat_nrows(X);
|
|
m = acb_mat_ncols(X);
|
|
|
|
if (X == B)
|
|
{
|
|
acb_ptr tmp = flint_malloc(sizeof(acb_struct) * n);
|
|
|
|
for (c = 0; c < m; c++)
|
|
{
|
|
for (i = 0; i < n; i++)
|
|
tmp[i] = B->rows[perm[i]][c];
|
|
for (i = 0; i < n; i++)
|
|
X->rows[i][c] = tmp[i];
|
|
}
|
|
|
|
flint_free(tmp);
|
|
}
|
|
else
|
|
{
|
|
for (c = 0; c < m; c++)
|
|
{
|
|
for (i = 0; i < n; i++)
|
|
{
|
|
acb_set(acb_mat_entry(X, i, c),
|
|
acb_mat_entry(B, perm[i], c));
|
|
}
|
|
}
|
|
}
|
|
|
|
acb_mat_get_mid(X, X);
|
|
|
|
/* todo: solve_tril and solve_triu have some overhead; should be
|
|
able to eliminate the basecase code below */
|
|
if (n >= 8 && m >= 8)
|
|
{
|
|
acb_mat_approx_solve_tril(X, A, X, 1, prec);
|
|
acb_mat_approx_solve_triu(X, A, X, 0, prec);
|
|
return;
|
|
}
|
|
|
|
acb_init(t);
|
|
|
|
for (c = 0; c < m; c++)
|
|
{
|
|
/* solve Ly = b */
|
|
for (i = 1; i < n; i++)
|
|
{
|
|
for (j = 0; j < i; j++)
|
|
{
|
|
_acb_approx_submul(acb_mat_entry(X, i, c),
|
|
acb_mat_entry(A, i, j), acb_mat_entry(X, j, c), t, prec);
|
|
}
|
|
}
|
|
|
|
/* solve Ux = y */
|
|
for (i = n - 1; i >= 0; i--)
|
|
{
|
|
for (j = i + 1; j < n; j++)
|
|
{
|
|
_acb_approx_submul(acb_mat_entry(X, i, c),
|
|
acb_mat_entry(A, i, j), acb_mat_entry(X, j, c), t, prec);
|
|
}
|
|
|
|
_acb_approx_div(acb_mat_entry(X, i, c), acb_mat_entry(X, i, c),
|
|
acb_mat_entry(A, i, i), t, prec);
|
|
}
|
|
}
|
|
|
|
acb_clear(t);
|
|
}
|
|
|