ARGUMENTS

NAME

rfft3f - compute the Fourier coefficients of a real periodic sequence. The RFFT operations are unnormalized, so a call of RFFT3F followed by a call of RFFT3B will multiply the input sequence by M*N*K.

SYNOPSIS

  SUBROUTINE RFFT3F( PLACE, FULL, M, N, K, A, LDA, B, LDB, WORK, 
 *      LWORK)
  CHARACTER * 1 PLACE, FULL
  INTEGER M, N, K, LDA, LDB, LWORK
  REAL A(LDA,N,*), B(LDB,N,*), WORK(*)

  SUBROUTINE RFFT3F_64( PLACE, FULL, M, N, K, A, LDA, B, LDB, WORK, 
 *      LWORK)
  CHARACTER * 1 PLACE, FULL
  INTEGER*8 M, N, K, LDA, LDB, LWORK
  REAL A(LDA,N,*), B(LDB,N,*), WORK(*)

F95 INTERFACE

  SUBROUTINE FFT3F( PLACE, FULL, [M], [N], [K], A, [LDA], B, [LDB], 
 *       WORK, LWORK)
  CHARACTER(LEN=1) :: PLACE, FULL
  INTEGER :: M, N, K, LDA, LDB, LWORK
  REAL, DIMENSION(:) :: WORK
  REAL, DIMENSION(:,:,:) :: A, B

  SUBROUTINE FFT3F_64( PLACE, FULL, [M], [N], [K], A, [LDA], B, [LDB], 
 *       WORK, LWORK)
  CHARACTER(LEN=1) :: PLACE, FULL
  INTEGER(8) :: M, N, K, LDA, LDB, LWORK
  REAL, DIMENSION(:) :: WORK
  REAL, DIMENSION(:,:,:) :: A, B

C INTERFACE

#include <sunperf.h>

void rfft3f(char place, char full, int m, int n, int k, float *a, int lda, float *b, int ldb, float *work, int lwork);

void rfft3f_64(char place, char full, long m, long n, long k, float *a, long lda, float *b, long ldb, float *work, long lwork);

ARGUMENTS

PLACE (input)
Select an in-place ('I' or 'i') or out-of-place ('O' or 'o') transform.
FULL (input)
Select a full ('F' or 'f') or partial (' ') representation of the results. If the caller selects full representation then an MxNxK real array will transform to produce an MxNxK complex array. If the caller does not select full representation then an MxNxK real array will transform to a (M/2+1)xNxK complex array that takes advantage of the symmetry properties of a transformed real sequence.
M (input)
Integer specifying the number of rows to be transformed. It is most efficient when M is a product of small primes. M > = 0; when M = 0, the subroutine returns immediately without changing any data.
N (input)
Integer specifying the number of columns to be transformed. It is most efficient when N is a product of small primes. N > = 0; when N = 0, the subroutine returns immediately without changing any data.
K (input)
Integer specifying the number of planes to be transformed. It is most efficient when K is a product of small primes. K > = 0; when K = 0, the subroutine returns immediately without changing any data.
A (input/output)
On entry, a three-dimensional array A(LDA,N,K) that contains input data to be transformed. On exit, if an in-place transform is done and FULL is not 'F' or 'f', A(1:2*(M/2+1),1:N,1:K) will contain the partial transformed results. If FULL = 'F' or 'f', A(1:2*M,1:N,1:K) will contain the complete transformed results.
LDA (input)
Leading dimension of the array containing the data to be transformed. LDA must be even if the transformed sequences are to be stored in A.
If PLACE = ('O' or 'o') LDA > = M

If PLACE = ('I' or 'i') LDA must be even. If

FULL = ('F' or 'f'), LDA > = 2*M

FULL is not ('F' or 'f'), LDA > = 2*(M/2+1)
B (input/output)
Upon exit, a three-dimensional array B(2*LDB,N,K) that contains the transformed results if an out-of-place transform is done. Otherwise, B is not used.
If an out-of-place transform is done and FULL is not 'F' or 'f', B(1:2*(M/2+1),1:N,1:K) will contain the partial transformed results. If FULL = 'F' or 'f', B(1:2*M,1:N,1:K) will contain the complete transformed results.
LDB (input)
2*LDB is the leading dimension of the array B. If an in-place transform is desired LDB is ignored.
If PLACE is ('O' or 'o') and

FULL is ('F' or 'f'), then LDB > = M

FULL is not ('F' or 'f'), then LDB > = M/2 + 1

Note that even though LDB is used in the argument list, 2*LDB is the actual leading dimension of B.
WORK (input/output)
One-dimensional real array of length at least LWORK. WORK must have been initialized by RFFT3I.
LWORK (input)
Integer. LWORK > = (M + 2*(N + K) + 4*K + 45).