arb/arb_hypgeom/airy_series.c
2016-09-05 20:54:16 +02:00

127 lines
3.4 KiB
C

/*
Copyright (C) 2016 Fredrik Johansson
This file is part of Arb.
Arb is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version. See <http://www.gnu.org/licenses/>.
*/
#include "arb_hypgeom.h"
void
_arb_hypgeom_airy_series(arb_ptr ai, arb_ptr ai_prime,
arb_ptr bi, arb_ptr bi_prime, arb_srcptr z, slong zlen, slong len, slong prec)
{
arb_ptr t, u, v;
slong tlen = len + ((ai_prime != NULL) || (bi_prime != NULL));
zlen = FLINT_MIN(zlen, len);
if (zlen <= 0)
return;
if (zlen == 1)
{
arb_hypgeom_airy(ai, ai_prime, bi, bi_prime, z, prec);
return;
}
t = _arb_vec_init(tlen);
u = _arb_vec_init(tlen);
v = _arb_vec_init(len);
arb_hypgeom_airy_jet((ai || ai_prime) ? t : NULL,
(bi || bi_prime) ? u : NULL, z, tlen, prec);
/* compose with nonconstant part */
arb_zero(v);
_arb_vec_set(v + 1, z + 1, zlen - 1);
if (ai != NULL) _arb_poly_compose_series(ai, t, len, v, zlen, len, prec);
if (bi != NULL) _arb_poly_compose_series(bi, u, len, v, zlen, len, prec);
/* todo: use chain rule to avoid compositions for derivatives? */
if (ai_prime != NULL)
{
_arb_poly_derivative(t, t, len + 1, prec);
_arb_poly_compose_series(ai_prime, t, len, v, zlen, len, prec);
}
if (bi_prime != NULL)
{
_arb_poly_derivative(u, u, len + 1, prec);
_arb_poly_compose_series(bi_prime, u, len, v, zlen, len, prec);
}
_arb_vec_clear(t, tlen);
_arb_vec_clear(u, tlen);
_arb_vec_clear(v, len);
}
void
arb_hypgeom_airy_series(arb_poly_t ai, arb_poly_t ai_prime,
arb_poly_t bi, arb_poly_t bi_prime, const arb_poly_t z, slong len, slong prec)
{
if (len == 0)
{
if (ai != NULL) arb_poly_zero(ai);
if (ai_prime != NULL) arb_poly_zero(ai_prime);
if (bi != NULL) arb_poly_zero(bi);
if (bi_prime != NULL) arb_poly_zero(bi_prime);
return;
}
if (z->length <= 1)
len = 1;
if (ai != NULL) arb_poly_fit_length(ai, len);
if (ai_prime != NULL) arb_poly_fit_length(ai_prime, len);
if (bi != NULL) arb_poly_fit_length(bi, len);
if (bi_prime != NULL) arb_poly_fit_length(bi_prime, len);
if (z->length == 0)
{
arb_t t;
arb_init(t);
_arb_hypgeom_airy_series(
ai ? ai->coeffs : NULL, ai_prime ? ai_prime->coeffs : NULL,
bi ? bi->coeffs : NULL, bi_prime ? bi_prime->coeffs : NULL,
t, 1, len, prec);
arb_clear(t);
}
else
{
_arb_hypgeom_airy_series(
ai ? ai->coeffs : NULL, ai_prime ? ai_prime->coeffs : NULL,
bi ? bi->coeffs : NULL, bi_prime ? bi_prime->coeffs : NULL,
z->coeffs, z->length, len, prec);
}
if (ai != NULL)
{
_arb_poly_set_length(ai, len);
_arb_poly_normalise(ai);
}
if (ai_prime != NULL)
{
_arb_poly_set_length(ai_prime, len);
_arb_poly_normalise(ai_prime);
}
if (bi != NULL)
{
_arb_poly_set_length(bi, len);
_arb_poly_normalise(bi);
}
if (bi_prime != NULL)
{
_arb_poly_set_length(bi_prime, len);
_arb_poly_normalise(bi_prime);
}
}