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Function std.math.trigonometry.atan2

Calculates the arc tangent of y / x, returning a value ranging from -π to π.

real atan2 (
  real y,
  real x
) pure nothrow @nogc @trusted;

double atan2 (
  double y,
  double x
) pure nothrow @nogc @safe;

float atan2 (
  float y,
  float x
) pure nothrow @nogc @safe;

Special Values
y x atan(y, x)
NAN anything NAN
anything NAN NAN
±0.0 >0.0 ±0.0
±0.0 +0.0 ±0.0
±0.0 <0.0 ±π
±0.0 -0.0 ±π
>0.0 ±0.0 π/2
<0.0 ±0.0 -π/2
>0.0 ±0.0
±∞ anything ±π/2
>0.0 -∞ ±π
±∞ ±π/4
±∞ -∞ ±3π/4


import std.math.operations : isClose;
import std.math.constants : PI;
import std.math.algebraic : sqrt;

assert(atan2(1.0, sqrt(3.0)).isClose(PI / 6));


Walter Bright, Don Clugston, Conversion of CEPHES math library to D by Iain Buclaw and David Nadlinger


Boost License 1.0.