1 files changed, 25 insertions, 0 deletions
diff --git a/lib/std/math/complex/proj.zig b/lib/std/math/complex/proj.zig
new file mode 100644
index 0000000000..c8f2d9fc6d
--- /dev/null
+++ b/lib/std/math/complex/proj.zig
@@ -0,0 +1,25 @@
+const std = @import("../../std.zig");
+const testing = std.testing;
+const math = std.math;
+const cmath = math.complex;
+const Complex = cmath.Complex;
+
+/// Returns the projection of z onto the riemann sphere.
+pub fn proj(z: var) Complex(@typeOf(z.re)) {
+    const T = @typeOf(z.re);
+
+    if (math.isInf(z.re) or math.isInf(z.im)) {
+        return Complex(T).new(math.inf(T), math.copysign(T, 0, z.re));
+    }
+
+    return Complex(T).new(z.re, z.im);
+}
+
+const epsilon = 0.0001;
+
+test "complex.cproj" {
+    const a = Complex(f32).new(5, 3);
+    const c = proj(a);
+
+    testing.expect(c.re == 5 and c.im == 3);
+}