radix_sqrt_approx_rsqrtmul, radix_sqrt_approx
Synopsis
#include <flint/radix.h>void radix_sqrt_approx_rsqrtmul(nn_ptr q, nn_srcptr a, slong an, slong n, const radix_t radix)sourceWith a as for radix_rsqrt_approx, set (q, n + 2) to an approximation of \sqrt a \in [1/B, 1) with n fraction limbs and two integral limbs (normally zero, though the value can round up to 1), with absolute error less than 4 B^{-n}/\sqrt a. The error is proportional to 1/\sqrt a rather than to \sqrt a, because the corrections of the last iteration are multiplied by an approximation of 1/\sqrt a \le B.
Cite this page
The FLINT team, “radix_sqrt_approx_rsqrtmul, radix_sqrt_approx (radix.h),” FLINT: Fast Library for Number Theory, documentation, version 3.7.0-dev, 2026. https://flintlib.org/doc/radix/radix_sqrt_approx_rsqrtmul.html (generated 2026-10-20).
@misc{flint-doc-radix-radix-sqrt-approx-rsqrtmul,
author = {{The FLINT team}},
title = {{radix\_sqrt\_approx\_rsqrtmul, radix\_sqrt\_approx (radix.h)}},
howpublished = {FLINT: Fast Library for Number Theory, documentation, version 3.7.0-dev},
year = {2026},
url = {https://flintlib.org/doc/radix/radix_sqrt_approx_rsqrtmul.html},
note = {Generated 2026-10-20}
}