FFT1D optimization for low sizes + test

VoidXH · Oct 10, 2023 · 904dd56 · 904dd56
1 parent 5c58e2a
commit 904dd56
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Showing 2 changed files with 17 additions and 1 deletion.
diff --git a/Cavern/Utilities/Measurements.FFT.cs b/Cavern/Utilities/Measurements.FFT.cs
@@ -219,9 +219,12 @@ static void ProcessFFT(float[] samples, FFTCache cache) {
             if (CavernAmp.IsMono()) {
                 ProcessFFT_Mono(even, cache, --depth);
                 ProcessFFT_Mono(odd, cache, depth);
-            } else {
+            } else if (even.Length != 4) {
                 ProcessFFT(even, cache, --depth);
                 ProcessFFT(odd, cache, depth);
+            } else {
+                ProcessFFT4(even);
+                ProcessFFT4(odd);
             }
 
             float[] cosCache = FFTCache.cos[depth + 1],

diff --git a/Tests/Test.Cavern/Measurements_Tests.cs b/Tests/Test.Cavern/Measurements_Tests.cs
@@ -54,6 +54,19 @@ public void FFT_IFFT_Sine() {
             }
         }
 
+        /// <summary>
+        /// Tests the FFT variant which optimizes the first step of the FFT to keep an absolute result.
+        /// </summary>
+        [TestMethod, Timeout(1000)]
+        public void FFT1D() {
+            float[] signal = new float[16];
+            signal[0] = 1;
+            float[] fft = signal.FFT1D();
+            for (int i = 0; i < fft.Length; i++) {
+                Assert.IsTrue(fft[i] == 1);
+            }
+        }
+
         /// <summary>
         /// Tests an FFT with a length of 4, which is calling a hardcoded FFT variant.
         /// </summary>