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NAME
     dfft2i - initialize the array xWSAVE, which is used in  both
     xFFT2F and xFFT2B.

SYNOPSIS
     SUBROUTINE RFFT2I(M, N, RWSAVE)

     SUBROUTINE DFFT2I(M, N, DWSAVE)

     SUBROUTINE CFFT2I(M, N, RWSAVE)

     SUBROUTINE ZFFT2I(M, N, DWSAVE)



     #include <sunperf.h>

     void rfft2i(int m, int n, float *wsave) ;

     void dfft2i(int m, int n, double *wsave) ;

     void cfft2i(int m, int n, complex *wsave) ;

     void zfft2i(int m, int n, doublecomplex *wsave) ;

ARGUMENTS
     M         Number of rows to be transformed.  M >= 0.

     N         Number of columns to be transformed.  N >= 0.

     xWSAVE    On entry, an array with dimension of at least (M +
               N  + MAX(M,N) + 40) for real inputs or (2 * (M + N
               + MAX(M,N)) + 40) for complex  inputs.   The  same
               work array can be used for both xFFTF and xFFTB as
               long as N  remains  unchanged.   Different  xWSAVE
               arrays  are  required  for  different values of N.
               This initialization does not have to  be  repeated
               between  calls  to xFFTF or xFFTB as long as N and
               xWSAVE   remain   unchanged,    thus    subsequent
               transforms can be obtained faster than the first.

SAMPLE PROGRAM
           PROGRAM TEST
           IMPLICIT NONE
     C
           INTEGER           M, N
           PARAMETER        (M = 2)
           PARAMETER        (N = 4)
     C
           INTEGER           I, J
           REAL              PI, WSAVE(4 * (M + N + N) + 40)
           REAL              X, Y
           COMPLEX           C(M,N)
     C
           EXTERNAL          CFFT2B, CFFT2F, CFFT2I
           INTRINSIC         ACOS, CMPLX, COS, SIN
     C
     C     Initialize the array C to a complex sequence.
     C
           PI = ACOS (-1.0)
           DO 110, J = 1, N
             DO 100, I = 1, M
               X = SIN ((I - 1.0) * 2.0 * PI / N)
               Y = COS ((J - 1.0) * 2.0 * PI / M)
               C(I,J) = CMPLX (X, Y)
       100   CONTINUE
       110 CONTINUE
     C
           PRINT 1000
           DO 200, I = 1, M
             PRINT 1010, (C(I,J), J = 1, N)
       200 CONTINUE
           CALL CFFT2I (M, N, WSAVE)
           CALL CFFT2F (M, N, C, M, WSAVE)
           PRINT 1020
           DO 300, I = 1, M
             PRINT 1010, (C(I,J), J = 1, N)
       300 CONTINUE
           CALL CFFT2B (M, N, C, M, WSAVE)
           PRINT 1030
           DO 400, I = 1, M
             PRINT 1010, (C(I,J), J = 1, N)
       400 CONTINUE
     C
      1000 FORMAT (1X, 'Original Sequences:')
      1010 FORMAT (1X, 100(F4.1' +',F4.1,'i  '))
      1020 FORMAT (1X, 'Transformed Sequences:')
      1030 FORMAT (1X, 'Recovered Sequences:')
     C
           END

SAMPLE OUTPUT
       0.0 + 1.0i   0.0 +-1.0i   0.0 + 1.0i   0.0 +-1.0i
       1.0 + 1.0i   1.0 +-1.0i   1.0 + 1.0i   1.0 +-1.0i
      Transformed Sequences:
       4.0 + 0.0i   0.0 + 0.0i   0.0 + 8.0i   0.0 + 0.0i
      -4.0 + 0.0i   0.0 + 0.0i   0.0 + 0.0i   0.0 + 0.0i
      Recovered Sequences:
       0.0 + 8.0i   0.0 +-8.0i   0.0 + 8.0i   0.0 +-8.0i
       8.0 + 8.0i   8.0 +-8.0i   8.0 + 8.0i   8.0 +-8.0i

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