pqc/external/flint-2.4.3/fq_mat_templates/lu_recursive.c

159 lines
4.3 KiB
C
Raw Normal View History

2014-05-18 22:03:37 +00:00
/*=============================================================================
This file is part of FLINT.
FLINT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FLINT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with FLINT; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2011 Fredrik Johansson
Copyright (C) 2013 Mike Hansen
Loosely based on the recursive PLS implementation in M4RI,
Copyright (C) 2008 Clement Pernet.
******************************************************************************/
#ifdef T
#include "templates.h"
#include <stdio.h>
static void
_apply_permutation(slong * AP,
TEMPLATE(T, mat_t) A, slong * P, slong n, slong offset)
{
if (n != 0)
{
TEMPLATE(T, struct) ** Atmp;
slong *APtmp;
slong i;
Atmp = flint_malloc(sizeof(TEMPLATE(T, struct) *) * n);
APtmp = flint_malloc(sizeof(slong) * n);
for (i = 0; i < n; i++)
Atmp[i] = A->rows[P[i] + offset];
for (i = 0; i < n; i++)
A->rows[i + offset] = Atmp[i];
for (i = 0; i < n; i++)
APtmp[i] = AP[P[i] + offset];
for (i = 0; i < n; i++)
AP[i + offset] = APtmp[i];
flint_free(Atmp);
flint_free(APtmp);
}
}
slong
TEMPLATE(T, mat_lu_recursive) (slong * P,
TEMPLATE(T, mat_t) A,
int rank_check, const TEMPLATE(T, ctx_t) ctx)
{
slong i, j, m, n, r1, r2, n1;
TEMPLATE(T, mat_t) A0, A1, A00, A01, A10, A11;
slong *P1;
m = A->r;
n = A->c;
if (m < TEMPLATE(CAP_T, MAT_LU_RECURSIVE_CUTOFF)
|| n < TEMPLATE(CAP_T, MAT_LU_RECURSIVE_CUTOFF))
{
r1 = TEMPLATE(T, mat_lu_classical) (P, A, rank_check, ctx);
return r1;
}
n1 = n / 2;
for (i = 0; i < m; i++)
P[i] = i;
P1 = flint_malloc(sizeof(slong) * m);
TEMPLATE(T, mat_window_init) (A0, A, 0, 0, m, n1, ctx);
TEMPLATE(T, mat_window_init) (A1, A, 0, n1, m, n, ctx);
r1 = TEMPLATE(T, mat_lu) (P1, A0, rank_check, ctx);
if (rank_check && (r1 != n1))
{
flint_free(P1);
TEMPLATE(T, mat_window_clear) (A0, ctx);
TEMPLATE(T, mat_window_clear) (A1, ctx);
return 0;
}
if (r1 != 0)
{
_apply_permutation(P, A, P1, m, 0);
}
TEMPLATE(T, mat_window_init) (A00, A, 0, 0, r1, r1, ctx);
TEMPLATE(T, mat_window_init) (A10, A, r1, 0, m, r1, ctx);
TEMPLATE(T, mat_window_init) (A01, A, 0, n1, r1, n, ctx);
TEMPLATE(T, mat_window_init) (A11, A, r1, n1, m, n, ctx);
if (r1 != 0)
{
TEMPLATE(T, mat_solve_tril) (A01, A00, A01, 1, ctx);
TEMPLATE(T, mat_submul) (A11, A11, A10, A01, ctx);
}
r2 = TEMPLATE(T, mat_lu) (P1, A11, rank_check, ctx);
if (rank_check && (r1 + r2 < FLINT_MIN(m, n)))
{
r1 = r2 = 0;
}
else
{
_apply_permutation(P, A, P1, m - r1, r1);
/* Compress L */
if (r1 != n1)
{
for (i = 0; i < m - r1; i++)
{
TEMPLATE(T, struct) * row = A->rows[r1 + i];
for (j = 0; j < FLINT_MIN(i, r2); j++)
{
TEMPLATE(T, set) (row + r1 + j, row + n1 + j, ctx);
TEMPLATE(T, zero) (row + n1 + j, ctx);
}
}
}
}
flint_free(P1);
TEMPLATE(T, mat_window_clear) (A00, ctx);
TEMPLATE(T, mat_window_clear) (A01, ctx);
TEMPLATE(T, mat_window_clear) (A10, ctx);
TEMPLATE(T, mat_window_clear) (A11, ctx);
TEMPLATE(T, mat_window_clear) (A0, ctx);
TEMPLATE(T, mat_window_clear) (A1, ctx);
return r1 + r2;
}
#endif