111 lines
3.1 KiB
C
111 lines
3.1 KiB
C
|
/*=============================================================================
|
||
|
|
|
||
|
|
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
|
||
|
|
|
||
|
|
******************************************************************************/
|
||
|
|
|
||
|
|
#include "fmpq_mat.h"
|
||
|
|
|
||
|
|
int fmpq_mat_inv(fmpq_mat_t B, const fmpq_mat_t A)
|
||
|
|
{
|
||
|
|
slong n = A->r;
|
||
|
|
|
||
|
|
if (n == 0)
|
||
|
|
{
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
else if (n == 1)
|
||
|
|
{
|
||
|
|
if (fmpq_is_zero(fmpq_mat_entry(A, 0, 0)))
|
||
|
|
return 0;
|
||
|
|
fmpq_inv(fmpq_mat_entry(B, 0, 0), fmpq_mat_entry(A, 0, 0));
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
else if (n == 2)
|
||
|
|
{
|
||
|
|
fmpq_t d;
|
||
|
|
int success;
|
||
|
|
|
||
|
|
fmpq_init(d);
|
||
|
|
|
||
|
|
fmpq_mul(d, fmpq_mat_entry(A, 0, 0), fmpq_mat_entry(A, 1, 1));
|
||
|
|
fmpq_submul(d, fmpq_mat_entry(A, 0, 1), fmpq_mat_entry(A, 1, 0));
|
||
|
|
success = !fmpq_is_zero(d);
|
||
|
|
|
||
|
|
if (success)
|
||
|
|
{
|
||
|
|
fmpq_t t00, t01, t10, t11;
|
||
|
|
fmpq_inv(d, d);
|
||
|
|
|
||
|
|
fmpq_init(t00);
|
||
|
|
fmpq_init(t01);
|
||
|
|
fmpq_init(t10);
|
||
|
|
fmpq_init(t11);
|
||
|
|
|
||
|
|
fmpq_mul(t00, fmpq_mat_entry(A, 1, 1), d);
|
||
|
|
fmpq_mul(t01, fmpq_mat_entry(A, 0, 1), d);
|
||
|
|
fmpq_mul(t10, fmpq_mat_entry(A, 1, 0), d);
|
||
|
|
fmpq_mul(t11, fmpq_mat_entry(A, 0, 0), d);
|
||
|
|
|
||
|
|
fmpq_set(fmpq_mat_entry(B, 0, 0), t00);
|
||
|
|
fmpq_neg(fmpq_mat_entry(B, 0, 1), t01);
|
||
|
|
fmpq_neg(fmpq_mat_entry(B, 1, 0), t10);
|
||
|
|
fmpq_set(fmpq_mat_entry(B, 1, 1), t11);
|
||
|
|
|
||
|
|
fmpq_clear(t00);
|
||
|
|
fmpq_clear(t01);
|
||
|
|
fmpq_clear(t10);
|
||
|
|
fmpq_clear(t11);
|
||
|
|
}
|
||
|
|
|
||
|
|
fmpq_clear(d);
|
||
|
|
return success;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
fmpz_mat_t Aclear, Bclear, I;
|
||
|
|
fmpz * den;
|
||
|
|
slong i;
|
||
|
|
int success;
|
||
|
|
|
||
|
|
fmpz_mat_init(Aclear, n, n);
|
||
|
|
fmpz_mat_init(Bclear, n, n);
|
||
|
|
fmpz_mat_init(I, n, n);
|
||
|
|
den = _fmpz_vec_init(n);
|
||
|
|
|
||
|
|
fmpq_mat_get_fmpz_mat_rowwise(Aclear, den, A);
|
||
|
|
for (i = 0; i < n; i++)
|
||
|
|
fmpz_set(fmpz_mat_entry(I, i, i), den + i);
|
||
|
|
|
||
|
|
success = fmpz_mat_solve(Bclear, den, Aclear, I);
|
||
|
|
if (success)
|
||
|
|
fmpq_mat_set_fmpz_mat_div_fmpz(B, Bclear, den);
|
||
|
|
|
||
|
|
fmpz_mat_clear(Aclear);
|
||
|
|
fmpz_mat_clear(Bclear);
|
||
|
|
fmpz_mat_clear(I);
|
||
|
|
_fmpz_vec_clear(den, A->r);
|
||
|
|
|
||
|
|
return success;
|
||
|
|
}
|
||
|
|
}
|