cfft1i

NAME

CFFT1I - initialization routine for CFFT1B and CFFT1F

SYNOPSIS

 SUBROUTINE CFFT1I (N, WSAVE, LENSAV, IER)
 INTEGER    N, LENSAV, IER
 REAL       WSAVE(LENSAV)

DESCRIPTION

 FFTPACK 5.0 subroutine CFFT1I initializes array WSAVE for use in 
 its companion routines CFFT1B and CFFT1F.  Routine CFFT1I must 
 be called before the first call to  CFFT1B or CFFT1F, and after 
 whenever the value of integer N changes.
 
 Input Arguments
 
 N       Integer length of the sequence to be transformed.  The 
         transform is most efficient when N is a product of 
         small primes.
 
 LENSAV  Integer dimension of WSAVE array.  LENSAV must be at least 
         2*N + INT(LOG(REAL(N))) + 4.


 Output Arguments
 
 WSAVE   Real work array with dimension LENSAV, containing the
         prime factors of N and also containing certain trigonometric 
         values which will be used in routines CFFT1B or CFFT1F.


 IER     = 0 successful exit
         = 2 input parameter LENSAV not big enough