FLINT3.7.0-dev
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_gr_dft_nfixed_roots, _gr_dft_nfixed_root_err_bound, _gr_dft_nfixed_cmul_err_ulps

Synopsis#include <flint/gr_dft.h>
int _gr_dft_nfixed_roots(gr_ptr roots, ulong n, double * err_ulps, gr_ctx_t ctx)source
double _gr_dft_nfixed_root_err_bound(ulong n, double kmul)source
double _gr_dft_nfixed_cmul_err_ulps(gr_ctx_t ctx)source

The root table of a fixed-point plan and its error bounds. The first function sets roots to approximations of e−2πij/ne^{-2\pi i j/n}, 0≤j<n0 \le j < n, over the complex fixed-point context ctx and writes a bound for their errors, in ulp, to err_ulps. The second bounds the error of the entries of a table of length nn built with products whose rounding error is at most kmul ulp in modulus. The third returns the error bound per part of one complex multiplication in ctx: 2, 4 or 6 ulp.

Cite this page

The FLINT team, “_gr_dft_nfixed_roots, _gr_dft_nfixed_root_err_bound, _gr_dft_nfixed_cmul_err_ulps (gr_dft.h),” FLINT: Fast Library for Number Theory, documentation, version 3.7.0-dev, 2026. https://flintlib.org/doc/gr_dft/_gr_dft_nfixed_roots.html (generated 2026-11-02).