ca_csgn
Synopsis
#include <flint/ca.h>Sets res to the extension of the real sign function that is 1 in the open right half-plane, -1 in the open left half-plane, and the sign of the imaginary part on the imaginary axis; equivalently \operatorname{csgn}(z) = z / \sqrt{z^2} for z \ne 0, and \operatorname{csgn}(0) = 0. For a signed infinity \operatorname{csgn}(c \infty) = \operatorname{csgn}(c); unsigned infinity gives Undefined. The result is Unknown when the required sign tests fail.
Cite this page
The FLINT team, “ca_csgn (ca.h),” FLINT: Fast Library for Number Theory, documentation, version 3.7.0-dev, 2026. https://flintlib.org/doc/ca/ca_csgn.html (generated 2026-10-20).
@misc{flint-doc-ca-ca-csgn,
author = {{The FLINT team}},
title = {{ca\_csgn (ca.h)}},
howpublished = {FLINT: Fast Library for Number Theory, documentation, version 3.7.0-dev},
year = {2026},
url = {https://flintlib.org/doc/ca/ca_csgn.html},
note = {Generated 2026-10-20}
}