// convert factorized form to number
void
bs_mul(mpz_t r, long int a, long int b)
{
long int i, j;
if (b-a<=32) {
mpz_set_ui(r, 1);
for (i=a; i<b; i++)
for (j=0; j<fmul[0].pow[i]; j++)
mpz_mul_ui(r, r, fmul[0].fac[i]);
} else {
mpz_t r2;
mpz_init(r2);
bs_mul(r2, a, (a+b)/2);
bs_mul(r, (a+b)/2, b);
mpz_mul(r, r, r2);
mpz_clear(r2);
}
}
/* f /= gcd(f,g), g /= gcd(f,g) */
void
fac_remove_gcd(mpz_t p, fac_t fp, mpz_t g, fac_t fg)
{
long int i, j, k, c;
fac_resize(fmul, min(fp->num_facs, fg->num_facs));
for (i=j=k=0; i<fp->num_facs && j<fg->num_facs; ) {
if (fp->fac[i] == fg->fac[j]) {
c = min(fp->pow[i], fg->pow[j]);
fp->pow[i] -= c;
fg->pow[j] -= c;
fmul->fac[k] = fp->fac[i];
fmul->pow[k] = c;
i++; j++; k++;
} else if (fp->fac[i] < fg->fac[j]) {
i++;
} else {
j++;
}
}
fmul->num_facs = k;
assert(k <= fmul->max_facs);
if (fmul->num_facs) {
bs_mul(gcd, 0, fmul->num_facs);
#if HAVE_DIVEXACT_PREINV
mpz_invert_mod_2exp (mgcd, gcd);
mpz_divexact_pre (p, p, gcd, mgcd);
mpz_divexact_pre (g, g, gcd, mgcd);
#else
#define SIZ(x) x->_mp_size
mpz_divexact(p, p, gcd);
mpz_divexact(g, g, gcd);
#endif
fac_compact(fp);
fac_compact(fg);
}
}