NAME

rfft3b - compute a periodic sequence from its Fourier coefficients.  The xFFT operations are unnormalized, so a call of xFFT3F followed by a call of xFFT3B will multiply the input sequence by M∗N∗K. 

SYNOPSIS

SUBROUTINE RFFT3B (PLACE, M, N, K, SX, LDX, SY, LDY, RWSAVE, LWSAVE)

SUBROUTINE DFFT3B (PLACE, M, N, K, DX, LDX, DY, LDY, DWSAVE, LWSAVE)

#include <sunperf.h>

void rfft3b (char place, int m, int n, int k, float ∗sx, int ldx, float ∗sy, int ldy, float ∗wsave, int lwsave) ;

void dfft3b (char place, int m, int n, int k, double ∗dx, int ldx, double ∗dy, int ldy, double ∗wsave, int lwsave) ;

ARGUMENTS

PLACE Select an in-place (’I’ or ’i’) or out-of-place (’O’ or ’o’) transform. 

M Number of rows to be transformed.  These subroutines are most efficient when M is a product of small primes.  M >= 0. 

N Number of columns to be transformed.  These subroutines are most efficient when N is a product of small primes.  N >= 0. 

K Number of planes to be transformed.  These subroutines are most efficient when K is a product of small primes.  K >= 0. 

xX On entry, if the caller selected an in-place transform then xX is a three-dimensional array xX(LDX,N,K) that contains the sequences to be transformed.  On exit, the transformed sequences. 

LDX Leading dimension of the array containing the data to be transformed.  LDX >= M. 

xY On entry, if the caller selected an out-of-place transform then xY is a three-dimensional array xY(LDY,N,K) that contains the sequences to be transformed.  If the caller selected an in-place transform then this argument is never referenced. 

LDY Leading dimension of the array for an out-of-place transform.  LDY >= M. 

xWSAVE Scratch array.  The array must have been initialized by xFFT3I. 

LWSAVE Length of the WSAVE array.  LWSAVE >= (M + N + MAX(M,N,K) + 45). 

SunOS 5.0  —  Last change: 10 Dec 1998