function crosscorr,A,B
; Computes the cross correlation of two real arrays A and B (same size)

f=A-mean(A)
g=B-mean(B)
cc=fft(fft(f,1)*conj(fft(g,1)),-1)
c1=total(f^2)
c2=total(g^2)
cc=cc/sqrt(c1*c2)

return,cc
end