void
_acb_poly_compose_series_brent_kung(acb_ptr res,
acb_srcptr poly1, long len1,
acb_srcptr poly2, long len2, long n, long prec)
{
acb_mat_t A, B, C;
acb_ptr t, h;
long i, m;
if (n == 1)
{
acb_set(res, poly1);
return;
}
m = n_sqrt(n) + 1;
acb_mat_init(A, m, n);
acb_mat_init(B, m, m);
acb_mat_init(C, m, n);
h = _acb_vec_init(n);
t = _acb_vec_init(n);
/* Set rows of B to the segments of poly1 */
for (i = 0; i < len1 / m; i++)
_acb_vec_set(B->rows[i], poly1 + i*m, m);
_acb_vec_set(B->rows[i], poly1 + i*m, len1 % m);
/* Set rows of A to powers of poly2 */
acb_set_ui(A->rows[0] + 0, 1UL);
_acb_vec_set(A->rows[1], poly2, len2);
for (i = 2; i < m; i++)
_acb_poly_mullow(A->rows[i], A->rows[(i + 1) / 2], n, A->rows[i / 2], n, n, prec);
acb_mat_mul(C, B, A, prec);
/* Evaluate block composition using the Horner scheme */
_acb_vec_set(res, C->rows[m - 1], n);
_acb_poly_mullow(h, A->rows[m - 1], n, poly2, len2, n, prec);
for (i = m - 2; i >= 0; i--)
{
_acb_poly_mullow(t, res, n, h, n, n, prec);
_acb_poly_add(res, t, n, C->rows[i], n, prec);
}
_acb_vec_clear(h, n);
_acb_vec_clear(t, n);
acb_mat_clear(A);
acb_mat_clear(B);
acb_mat_clear(C);
}
void
acb_poly_add(acb_poly_t res, const acb_poly_t poly1,
const acb_poly_t poly2, long prec)
{
long max = FLINT_MAX(poly1->length, poly2->length);
acb_poly_fit_length(res, max);
_acb_poly_add(res->coeffs, poly1->coeffs, poly1->length, poly2->coeffs,
poly2->length, prec);
_acb_poly_set_length(res, max);
_acb_poly_normalise(res);
}
void
acb_poly_add_series(acb_poly_t res, const acb_poly_t poly1,
const acb_poly_t poly2, slong len, slong prec)
{
slong len1, len2;
len1 = poly1->length;
len2 = poly2->length;
len1 = FLINT_MIN(len1, len);
len2 = FLINT_MIN(len2, len);
len = FLINT_MAX(len1, len2);
acb_poly_fit_length(res, len);
_acb_poly_add(res->coeffs, poly1->coeffs, len1, poly2->coeffs, len2, prec);
_acb_poly_set_length(res, len);
_acb_poly_normalise(res);
}
void
_acb_poly_compose_series_horner(acb_ptr res, acb_srcptr poly1, slong len1,
acb_srcptr poly2, slong len2, slong n, slong prec)
{
if (n == 1)
{
acb_set(res, poly1);
}
else
{
slong i = len1 - 1;
slong lenr;
acb_ptr t = _acb_vec_init(n);
lenr = len2;
_acb_vec_scalar_mul(res, poly2, len2, poly1 + i, prec);
i--;
acb_add(res, res, poly1 + i, prec);
while (i > 0)
{
i--;
if (lenr + len2 - 1 < n)
{
_acb_poly_mul(t, res, lenr, poly2, len2, prec);
lenr = lenr + len2 - 1;
}
else
{
_acb_poly_mullow(t, res, lenr, poly2, len2, n, prec);
lenr = n;
}
_acb_poly_add(res, t, lenr, poly1 + i, 1, prec);
}
_acb_vec_zero(res + lenr, n - lenr);
_acb_vec_clear(t, n);
}
}