#include "gr_poly.h"
int
_gr_poly_evaluate_other_horner(gr_ptr res, gr_srcptr f, slong len, const gr_srcptr x, gr_ctx_t x_ctx, gr_ctx_t ctx)
{
int status = GR_SUCCESS;
if (len == 0)
{
return gr_zero(res, x_ctx);
}
else if (len == 1 || gr_is_zero(x, x_ctx) == T_TRUE)
{
return gr_set_other(res, f, ctx, x_ctx);
}
else if (len == 2)
{
slong sz = ctx->sizeof_elem;
status |= gr_mul_other(res, x, GR_ENTRY(f, 1, sz), ctx, x_ctx);
status |= gr_add_other(res, res, f, ctx, x_ctx);
return status;
}
else
{
slong i = len - 1;
slong sz = ctx->sizeof_elem;
gr_ptr t, u;
GR_TMP_INIT2(t, u, x_ctx);
status |= gr_set_other(u, GR_ENTRY(f, i, sz), ctx, x_ctx);
for (i = len - 2; i >= 0; i--)
{
status |= gr_mul(t, u, x, x_ctx);
status |= gr_add_other(u, t, GR_ENTRY(f, i, sz), ctx, x_ctx);
}
gr_swap(res, u, x_ctx);
GR_TMP_CLEAR2(t, u, x_ctx);
return status;
}
}
int
gr_poly_evaluate_other_horner(gr_ptr res, const gr_poly_t f, gr_srcptr a, gr_ctx_t a_ctx, gr_ctx_t ctx)
{
return _gr_poly_evaluate_other_horner(res, f->coeffs, f->length, a, a_ctx, ctx);
}