void
arb_poly_mullow_block(arb_poly_t res, const arb_poly_t poly1,
const arb_poly_t poly2, slong n, slong prec)
{
slong xlen, ylen, zlen;
xlen = poly1->length;
ylen = poly2->length;
if (xlen == 0 || ylen == 0 || n == 0)
{
arb_poly_zero(res);
return;
}
xlen = FLINT_MIN(xlen, n);
ylen = FLINT_MIN(ylen, n);
zlen = FLINT_MIN(xlen + ylen - 1, n);
if (res == poly1 || res == poly2)
{
arb_poly_t tmp;
arb_poly_init2(tmp, zlen);
_arb_poly_mullow_block(tmp->coeffs, poly1->coeffs, xlen,
poly2->coeffs, ylen, zlen, prec);
arb_poly_swap(res, tmp);
arb_poly_clear(tmp);
}
else
{
arb_poly_fit_length(res, zlen);
_arb_poly_mullow_block(res->coeffs, poly1->coeffs, xlen,
poly2->coeffs, ylen, zlen, prec);
}
_arb_poly_set_length(res, zlen);
_arb_poly_normalise(res);
}
void
_arb_poly_mullow(arb_ptr res,
arb_srcptr poly1, long len1,
arb_srcptr poly2, long len2, long n, long prec)
{
if (n == 1)
{
arb_mul(res, poly1, poly2, prec);
}
else
{
if (n < BLOCK_CUTOFF || len1 < BLOCK_CUTOFF || len2 < BLOCK_CUTOFF)
_arb_poly_mullow_classical(res, poly1, len1, poly2, len2, n, prec);
else
_arb_poly_mullow_block(res, poly1, len1, poly2, len2, n, prec);
}
}