mirror of
https://github.com/vale981/arb
synced 2025-03-05 17:31:38 -05:00
119 lines
2.8 KiB
C
119 lines
2.8 KiB
C
/*
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Copyright (C) 2018 arbguest
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This file is part of Arb.
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Arb is free software: you can redistribute it and/or modify it under
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the terms of the GNU Lesser General Public License (LGPL) as published
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by the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version. See <http://www.gnu.org/licenses/>.
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*/
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#include "acb_mat.h"
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static void
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_acb_approx_mul(acb_t res, const acb_t x, const acb_t y, slong prec)
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{
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arf_complex_mul(arb_midref(acb_realref(res)), arb_midref(acb_imagref(res)),
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arb_midref(acb_realref(x)), arb_midref(acb_imagref(x)),
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arb_midref(acb_realref(y)), arb_midref(acb_imagref(y)), prec, ARB_RND);
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}
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static void
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_acb_approx_inv(acb_t z, const acb_t x, slong prec)
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{
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arf_set(arb_midref(acb_realref(z)), arb_midref(acb_realref(x)));
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arf_set(arb_midref(acb_imagref(z)), arb_midref(acb_imagref(x)));
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mag_zero(arb_radref(acb_realref(z)));
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mag_zero(arb_radref(acb_imagref(z)));
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acb_inv(z, z, prec);
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mag_zero(arb_radref(acb_realref(z)));
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mag_zero(arb_radref(acb_imagref(z)));
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}
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static void
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_acb_vec_approx_scalar_addmul(acb_ptr res, acb_srcptr vec,
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slong len, const acb_t c, slong prec)
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{
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acb_t t;
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slong i;
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acb_init(t);
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for (i = 0; i < len; i++)
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{
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_acb_approx_mul(t, vec + i, c, prec);
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arf_add(arb_midref(acb_realref(res + i)),
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arb_midref(acb_realref(res + i)),
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arb_midref(acb_realref(t)), prec, ARB_RND);
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arf_add(arb_midref(acb_imagref(res + i)),
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arb_midref(acb_imagref(res + i)),
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arb_midref(acb_imagref(t)), prec, ARB_RND);
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}
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acb_clear(t);
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}
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int
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acb_mat_approx_lu(slong * P, acb_mat_t LU, const acb_mat_t A, slong prec)
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{
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acb_t d, e;
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acb_ptr * a;
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slong i, j, m, n, r, row, col;
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int result;
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if (acb_mat_is_empty(A))
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return 1;
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m = acb_mat_nrows(A);
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n = acb_mat_ncols(A);
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acb_mat_get_mid(LU, A);
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a = LU->rows;
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row = col = 0;
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for (i = 0; i < m; i++)
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P[i] = i;
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acb_init(d);
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acb_init(e);
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result = 1;
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while (row < m && col < n)
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{
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r = acb_mat_find_pivot_partial(LU, row, m, col);
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if (r == -1)
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{
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result = 0;
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break;
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}
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else if (r != row)
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acb_mat_swap_rows(LU, P, row, r);
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_acb_approx_inv(d, a[row] + col, prec);
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for (j = row + 1; j < m; j++)
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{
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_acb_approx_mul(e, a[j] + col, d, prec);
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acb_neg(e, e);
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_acb_vec_approx_scalar_addmul(a[j] + col,
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a[row] + col, n - col, e, prec);
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acb_zero(a[j] + col);
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acb_neg(a[j] + row, e);
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}
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row++;
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col++;
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}
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acb_clear(d);
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acb_clear(e);
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return result;
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}
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