A-M baby

Task/Fast-Fourier-transform/Go/fast-fourier-transform.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+    "fmt"
+    "math"
+    "math/cmplx"
+)
+
+func ditfft2(x []float64, y []complex128, n, s int) {
+    if n == 1 {
+        y[0] = complex(x[0], 0)
+        return
+    }
+    ditfft2(x, y, n/2, 2*s)
+    ditfft2(x[s:], y[n/2:], n/2, 2*s)
+    for k := 0; k < n/2; k++ {
+        tf := cmplx.Rect(1, -2*math.Pi*float64(k)/float64(n)) * y[k+n/2]
+        y[k], y[k+n/2] = y[k]+tf, y[k]-tf
+    }
+}
+
+func main() {
+    x := []float64{1, 1, 1, 1, 0, 0, 0, 0}
+    y := make([]complex128, len(x))
+    ditfft2(x, y, len(x), 1)
+    for _, c := range y {
+        fmt.Printf("%8.4f\n", c)
+    }
+}