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/*
Copyright (C) 2018 Tommy Hofmann
Copyright (C) 2021 Daniel Schultz
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "fmpz.h"
#include "fmpz_mod.h"
#include "fmpz_mod_mat.h"
int fmpz_mod_mat_inv(fmpz_mod_mat_t B, const fmpz_mod_mat_t A, const fmpz_mod_ctx_t ctx)
{
fmpz_mod_mat_t I;
slong dim;
int result;
dim = A->r;
switch (dim)
{
case 0:
result = 1;
break;
case 1:
if (fmpz_is_zero(fmpz_mod_mat_entry(A, 0, 0)))
{
result = 0;
}
else
{
fmpz_mod_inv(fmpz_mod_mat_entry(B, 0, 0),
fmpz_mod_mat_entry(A, 0, 0), ctx);
result = 1;
}
break;
default:
fmpz_mod_mat_init(I, dim, dim, ctx);
fmpz_mod_mat_one(I, ctx);
result = fmpz_mod_mat_solve(B, A, I, ctx);
fmpz_mod_mat_clear(I, ctx);
}
return result;
}