FLINT3.7.0-dev
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arb_atan2

Synopsis#include <flint/arb.h>
void arb_atan2(arb_t z, const arb_t b, const arb_t a, slong prec)source

Sets z to the argument (phase) of the complex number a+bia + bi, in (−π,π](-\pi, \pi], with the branch cut on (−∞,0](-\infty, 0]. By definition atan2⁡(0,0)=0\operatorname{atan2}(0, 0) = 0 and atan2⁡(0,a)=π\operatorname{atan2}(0, a) = \pi for a<0a < 0. A ball that straddles the branch cut gives an enclosure of [−π,π][-\pi, \pi].

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Cite this page

The FLINT team, “arb_atan2 (arb.h),” FLINT: Fast Library for Number Theory, documentation, version 3.7.0-dev, 2026. https://flintlib.org/doc/arb/arb_atan2.html (generated 2026-11-02).