arb/bool_mat/pow_ui.c
2016-02-28 21:24:27 -05:00

86 lines
2.2 KiB
C

/*=============================================================================
This file is part of ARB.
ARB 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.
ARB 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 ARB; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2016 Arb authors
******************************************************************************/
#include "bool_mat.h"
void
bool_mat_pow_ui(bool_mat_t B, const bool_mat_t A, ulong exp)
{
slong d;
if (!bool_mat_is_square(A))
{
flint_printf("bool_mat_pow_ui: a square matrix is required!\n");
abort();
}
if (bool_mat_is_empty(A))
return;
d = bool_mat_nrows(A);
if (exp <= 2 || d <= 1)
{
if (exp == 0)
{
bool_mat_one(B);
}
else if (d == 1)
{
*bool_mat_entry(B, 0, 0) = *bool_mat_entry(A, 0, 0);
}
else if (exp == 1)
{
bool_mat_set(B, A);
}
else if (exp == 2)
{
bool_mat_sqr(B, A);
}
}
else
{
slong i;
bool_mat_t T, U;
bool_mat_init(T, d, d);
bool_mat_set(T, A);
bool_mat_init(U, d, d);
for (i = ((slong) FLINT_BIT_COUNT(exp)) - 2; i >= 0; i--)
{
bool_mat_sqr(U, T);
if (exp & (WORD(1) << i))
bool_mat_mul(T, U, A);
else
bool_mat_swap(T, U);
}
bool_mat_swap(B, T);
bool_mat_clear(T);
bool_mat_clear(U);
}
}