pro lifetimf,in,out

; Procedure to compute a time correlation curve between patterns
; stored in a 3-d array IN. Reference frame is the first one.
; OUT is a 1-d array with the values
; of correlation, normalized to 1.
; 30 Nov 1995

on_error,1

msiz=size(in)
if msiz(0) ne 3 then message,'ERROR: Input array must be 3-D'
n=msiz(3)
out=fltarr(n)
arr=float(in)

arr(*,*,0)=float(in(*,*,0))-mean(float(in(*,*,0)))
den=total(arr(*,*,0)*arr(*,*,0))
out(0)=1.

for i=1,n-1 do begin
	arr(*,*,i)=float(in(*,*,i))-mean(float(in(*,*,i)))
       ;den=sqrt(total(arr(*,*,i)*arr(*,*,i))*den) ; otra formula
	out(i)=total(arr(*,*,0)*arr(*,*,i))/den
endfor

end