inline bool solveLinear(const DMatZZ& A,
const DMatZZ& B,
DMatZZ& X)
{
DMatZZ::ElementType den;
A.ring().init(den);
bool result = fmpz_mat_solve(X.fmpz_mat(), &den, B.fmpz_mat(), A.fmpz_mat());
if (!fmpz_is_pm1(&den))
result = false;
A.ring().clear(den);
return result;
}
int fmpq_mat_inv(fmpq_mat_t B, const fmpq_mat_t A)
{
long 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;
long 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;
}
}
