1 files changed, 11 insertions, 0 deletions
diff --git a/src/math/cmplx/phase.go b/src/math/cmplx/phase.go
new file mode 100644
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--- /dev/null
+++ b/src/math/cmplx/phase.go
@@ -0,0 +1,11 @@
+// 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 cmplx
+
+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)) }