mirror of
https://github.com/vale981/arb
synced 2025-03-06 01:41:39 -05:00
116 lines
3.3 KiB
C
116 lines
3.3 KiB
C
/*=============================================================================
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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
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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ARB is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with ARB; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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=============================================================================*/
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/******************************************************************************
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Copyright (C) 2015 Arb authors
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******************************************************************************/
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#include "arb_mat.h"
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void
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arb_mat_sqr_classical(arb_mat_t B, const arb_mat_t A, slong prec)
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{
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slong n, i, j, k;
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arb_t p, s;
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n = arb_mat_nrows(A);
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if (arb_mat_ncols(A) != n || arb_mat_nrows(B) != n || arb_mat_ncols(B) != n)
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{
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flint_printf("arb_mat_sqr: incompatible dimensions\n");
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abort();
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}
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if (n == 0)
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{
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arb_mat_zero(B);
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return;
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}
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if (n == 1)
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{
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arb_mul(arb_mat_entry(B, 0, 0),
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arb_mat_entry(A, 0, 0),
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arb_mat_entry(A, 0, 0), prec);
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return;
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}
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if (A == B)
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{
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arb_mat_t T;
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arb_mat_init(T, n, n);
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arb_mat_sqr(T, A, prec);
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arb_mat_swap(T, B);
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arb_mat_clear(T);
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return;
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}
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arb_init(p);
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arb_init(s);
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/* contribution of diagonal of A to diagonal of B */
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for (i = 0; i < n; i++)
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{
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arb_mul(arb_mat_entry(B, i, i),
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arb_mat_entry(A, i, i),
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arb_mat_entry(A, i, i), prec);
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}
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for (i = 0; i < n; i++)
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{
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for (j = 0; j < i; j++)
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{
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/* contribution of off-diagonal of A to diagonal of B */
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arb_mul(p, arb_mat_entry(A, i, j), arb_mat_entry(A, j, i), prec);
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arb_add(arb_mat_entry(B, i, i), arb_mat_entry(B, i, i), p, prec);
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arb_add(arb_mat_entry(B, j, j), arb_mat_entry(B, j, j), p, prec);
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/* contribution of diagonal of A to off-diagonal of B */
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arb_add(s, arb_mat_entry(A, i, i), arb_mat_entry(A, j, j), prec);
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arb_mul(arb_mat_entry(B, i, j), arb_mat_entry(A, i, j), s, prec);
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arb_mul(arb_mat_entry(B, j, i), arb_mat_entry(A, j, i), s, prec);
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}
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}
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/* contribution of off-diagonal of A to off-diagonal of B */
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if (n > 2)
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{
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for (i = 0; i < n; i++)
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{
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for (j = 0; j < n; j++)
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{
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for (k = 0; k < n; k++)
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{
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if (i != j && j != k && k != i)
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{
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arb_addmul(arb_mat_entry(B, i, j),
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arb_mat_entry(A, i, k),
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arb_mat_entry(A, k, j), prec);
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}
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}
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}
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}
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}
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arb_clear(p);
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arb_clear(s);
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}
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