1 // Copyright 2010 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package cmplx 6 7 import "math" 8 9 // Phase returns the phase (also called the argument) of x. 10 // The returned value is in the range [-Pi, Pi]. 11 func Phase(x complex128) float64 { return math.Atan2(imag(x), real(x)) } 12