1 files changed, 19 insertions, 0 deletions
diff --git a/lib/std/math/complex/arg.zig b/lib/std/math/complex/arg.zig
new file mode 100644
index 0000000000..d0c9588b8d
--- /dev/null
+++ b/lib/std/math/complex/arg.zig
@@ -0,0 +1,19 @@
+const std = @import("../../std.zig");
+const testing = std.testing;
+const math = std.math;
+const cmath = math.complex;
+const Complex = cmath.Complex;
+
+/// Returns the angular component (in radians) of z.
+pub fn arg(z: var) @typeOf(z.re) {
+    const T = @typeOf(z.re);
+    return math.atan2(T, z.im, z.re);
+}
+
+const epsilon = 0.0001;
+
+test "complex.carg" {
+    const a = Complex(f32).new(5, 3);
+    const c = arg(a);
+    testing.expect(math.approxEq(f32, c, 0.540420, epsilon));
+}