Visual Basic 常用数学算法集书中收录了所有代码

				Sub CORREL(DATA1(), DATA2(), N, ANS())
				    Dim FFT(128)
				    Call TWOFFT(DATA1(), DATA2(), FFT(), ANS(), N)
				    NO2 = N / 2#
				    For I = 1 To NO2 + 1
				      DUM = ANS(2 * I - 1)
				      DUM1 = FFT(2 * I - 1) * DUM + FFT(2 * I) * ANS(2 * I)
				      ANS(2 * I - 1) = DUM1 / CSng(NO2)
				      DUM2 = FFT(2 * I) * DUM - FFT(2 * I - 1) * ANS(2 * I)
				      ANS(2 * I) = DUM2 / CSng(NO2)
				    Next I
				    ANS(2) = ANS(N + 1)
				    Call REALFT(ANS(), NO2, -1)
				    Erase FFT
				End Sub