Initial commit

fft/fft.py

@@ -0,0 +1,31 @@
+import numpy as np
+
+
+def fft(x: np.array) -> np.array:
+    N = len(x)
+
+    if N == 1:
+        return x
+    else:
+        even_fft = fft(x[::2])
+        odd_fft = fft(x[1::2])
+
+        factors = np.exp(-2j * np.pi * np.arange(N) / N)
+
+        result = np.concatenate([even_fft + factors[:N // 2] * odd_fft,
+                                 even_fft + factors[N // 2:] * odd_fft])
+
+        return result
+
+
+def main():
+    x = np.arange(8)
+    fft(x)
+    # # x = np.random.normal(size=4)
+    # x = np.array([1, 0, 1, 0, 0, 0, 0, 0])
+    # print(f"own:\t{fft(x)}")
+    # print(f"numpy:\t{np.fft.fft(x)}")
+
+
+if __name__ == "__main__":
+    main()