src/pkg/cmath/phase.go

// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package cmath

import "math"

// Phase returns the phase (also called the argument) of x.
// The returned value is in the range [-Pi, Pi].
func Phase(x complex128) float64 { return math.Atan2(imag(x), real(x)) }