原来的代码中有以下注释:
! WSAVE A REAL WORK ARRAY WHICH MUST BE DIMENSIONED AT LEAST 4N+1
! IN THE PROGRAM THAT CALLS CFFTF. THE WSAVE ARRAY MUST BE
! INITIALIZED BY CALLING SUBROUTINE CFFTI(N,WSAVE) AND A
! DIFFERENT WSAVE ARRAY MUST BE USED FOR EACH DIFFERENT
! VALUE OF N. THIS INITIALIZATION DOES NOT HAVE TO BE
! REPEATED SO LONG AS N REMAINS UNCHANGED THUS SUBSEQUENT
! TRANSFORMS CAN BE OBTAINED FASTER THAN THE FIRST.
! THE SAME WSAVE ARRAY CAN BE USED BY CFFTF AND CFFTB.