Contents

• NAME
• SYNOPSIS
  • F95 INTERFACE
  • C INTERFACE
• ARGUMENTS

NAME

     cfft2b - compute a periodic sequence from its Fourier  coef-
     ficients.   The  xFFT operations are unnormalized, so a call
     of xFFT2F followed by a call of  xFFT2B  will  multiply  the
     input sequence by M*N.

SYNOPSIS

     SUBROUTINE CFFT2B(M, N, A, LDA, WORK, LWORK)

     COMPLEX A(LDA,*)
     INTEGER M, N, LDA, LWORK
     REAL WORK(*)

     SUBROUTINE CFFT2B_64(M, N, A, LDA, WORK, LWORK)

     COMPLEX A(LDA,*)
     INTEGER*8 M, N, LDA, LWORK
     REAL WORK(*)

  F95 INTERFACE
     SUBROUTINE FFT2B([M], [N], A, [LDA], WORK, LWORK)

     COMPLEX, DIMENSION(:,:) :: A
     INTEGER :: M, N, LDA, LWORK
     REAL, DIMENSION(:) :: WORK

     SUBROUTINE FFT2B_64([M], [N], A, [LDA], WORK, LWORK)

     COMPLEX, DIMENSION(:,:) :: A
     INTEGER(8) :: M, N, LDA, LWORK
     REAL, DIMENSION(:) :: WORK

  C INTERFACE
     #include <sunperf.h>

     void cfft2b(int m, int n, complex *a, int lda, float  *work,
               int lwork);

     void cfft2b_64(long m, long n, complex *a, long  lda,  float
               *work, long lwork);

ARGUMENTS

     M (input) Number of rows to be transformed.   These  subrou-
               tines  are  most  efficient when M is a product of
               small primes.  M >= 0.
     N (input) Number of columns to be transformed.   These  sub-
               routines are most efficient when N is a product of
               small primes.  N >= 0.

     A (input/output)
               On entry, a two-dimensional array A(M,N) that con-
               tains the sequences to be transformed.

     LDA (input)
               Leading dimension of the array containing the data
               to be transformed.  LDA >= M.

     WORK (input)
               On input, workspace WORK must have  been  initial-
               ized by CFFT2I.

     LWORK (input)
               The dimension of the array WORK.  LWORK >= (4 * (M
               + N) + 30)