Complex API additions

Cavern/Utilities/Complex.cs

@@ -29,6 +29,11 @@ public float Magnitude {
         /// </summary>
         public float Phase => MathF.Atan2(Imaginary, Real);
 
+        /// <summary>
+        /// Squared magnitude of the complex number.
+        /// </summary>
+        public float SqrMagnitude => Real * Real + Imaginary * Imaginary;
+
         /// <summary>
         /// Complex number from a scalar.
         /// </summary>

Cavern/Utilities/ComplexArray.cs

@@ -5,6 +5,21 @@ namespace Cavern.Utilities {
     /// Operations on complex arrays.
     /// </summary>
     public static class ComplexArray {
+        /// <summary>
+        /// Add the <paramref name="other"/> array's each element to the same indexes in the <paramref name="source"/>.
+        /// </summary>
+        public static unsafe void Add(this Complex[] source, Complex[] other) {
+            fixed (Complex* pSource = source)
+            fixed (Complex* pOther = other) {
+                Complex* lhs = pSource,
+                    rhs = pOther,
+                    end = pSource + source.Length;
+                while (lhs != end) {
+                    *lhs++ += *rhs++;
+                }
+            }
+        }
+
         /// <summary>
         /// Convert all elements in the <paramref name="source"/> to their conjugates.
         /// </summary>