void
_fmpq_submul(fmpz_t rnum, fmpz_t rden, const fmpz_t op1num, const fmpz_t op1den,
const fmpz_t op2num, const fmpz_t op2den)
{
fmpz_t u, v;
fmpz_init(u);
fmpz_init(v);
_fmpq_mul(u, v, op1num, op1den, op2num, op2den);
_fmpq_sub(rnum, rden, rnum, rden, u, v);
fmpz_clear(u);
fmpz_clear(v);
}
void _nf_elem_sub_lf(nf_elem_t a, const nf_elem_t b,
const nf_elem_t c, const nf_t nf, int can)
{
const fmpz * const p = LNF_ELEM_NUMREF(b);
const fmpz * const q = LNF_ELEM_DENREF(b);
const fmpz * const r = LNF_ELEM_NUMREF(c);
const fmpz * const s = LNF_ELEM_DENREF(c);
fmpz * const rnum = LNF_ELEM_NUMREF(a);
fmpz * const rden = LNF_ELEM_DENREF(a);
fmpz_t t;
if (can)
_fmpq_sub(rnum, rden, p, q, r, s);
else
{
/* Same denominator */
if (fmpz_equal(q, s))
{
fmpz_sub(rnum, p, r);
fmpz_set(rden, q);
return;
}
/* p/q is an integer */
if (fmpz_is_one(q))
{
fmpz_init(t);
fmpz_mul(t, p, s);
fmpz_sub(rnum, t, r);
fmpz_set(rden, s);
fmpz_clear(t);
return;
}
/* r/s is an integer */
if (fmpz_is_one(s))
{
fmpz_init(t);
fmpz_mul(t, r, q);
fmpz_sub(rnum, t, p);
fmpz_set(rden, q);
fmpz_clear(t);
return;
}
/*
We want to compute p/q - r/s which is (p*s - q*r, q*s).
*/
fmpz_init(t);
fmpz_mul(t, q, r);
fmpz_mul(rnum, p, s);
fmpz_sub(rnum, rnum, t);
fmpz_mul(rden, q, s);
fmpz_clear(t);
}
}
void fmpq_sub(fmpq_t res, const fmpq_t op1, const fmpq_t op2)
{
_fmpq_sub(fmpq_numref(res), fmpq_denref(res),
fmpq_numref(op1), fmpq_denref(op1),
fmpq_numref(op2), fmpq_denref(op2));
}
