HW8 Complete

HW8/main.py

@@ -0,0 +1,52 @@
+import math
+import time
+import numpy as np
+
+def saveResults(size, t):
+    with open("results.txt", "a") as myfile:
+        print("Size: " + str(size) + " Time: " + str(t), file=myfile)
+        myfile.flush()
+        myfile.close()
+
+def getV(n, sign):
+    v = []
+    for j in range(0, n):
+        v.append(complex(math.cos((j*2*math.pi)/n), math.sin((j*2*math.pi)/n)))
+    return v if sign == 1 else conjugate(v, n)
+
+def conjugate(v, n):
+    for j in range(0, n):
+        v[j] = v[j].conjugate()
+    return v
+
+def FFT(P, W, n):
+    if n == 1:
+        return [P[0]]
+    evenP = [P[j] for j in range(0, n, 2)]
+    oddP = [P[j] for j in range(1, n, 2)]
+    W2 = [W[j]*W[j] for j in range(0, n//2)]
+    sEven = FFT(evenP, W2, n//2)
+    sOdd = FFT(oddP, W2, n//2)
+    return [sEven[j]+W[j]*sOdd[j] for j in range(0, n//2)] + [sEven[j]-W[j]*sOdd[j] for j in range(0, n//2)]
+
+def main():
+    # n = 8
+    # p = [0, 1, 2, 3, 4, 5, 6, 7]
+    # print("Forward FFT")
+    # sol = FFT([complex(p[i], 0) for i in range(0, n)], getV(n, +1), n)
+    # print(sol)
+    # print("Inverse FFT")
+    # back = [s / 8 for s in FFT(sol, getV(n, -1), n)]
+    # print("Answer")
+    # print(back)
+    pow2 = []
+    for i in range(7, 55):
+        pow2.append(2 ** i)
+    for n in pow2:
+        P = np.arange(n)
+        start = time.time()
+        sol = FFT([complex(P[i], 0) for i in range(0, n)], getV(n, +1), n)
+        stop = time.time()
+        #inverseSol = FFT([complex(P[i], 0) for i in range(0, n)], getV(n, +1), n)
+        saveResults(n, stop-start)
+main()