CFFT3D - AMD Core Math Library (ACML) 4.4.0

— SUBROUTINE: CFFT3D (MODE,L,M,N,X,COMM,INFO)

— Input: INTEGER MODE

The value of MODE on input determines the direction of transform to be performed by CFFT3D.
On input:

MODE=-1 : forward 3D transform is performed.
MODE=1 : backward (reverse) 3D transform is performed.

— Input: INTEGER L

On input: the length of the first dimension of the 3D array of data to be transformed. If X is declared as a 3D array then L is the first dimension of X.

— Input: INTEGER M

On input: the length of the second dimension of the 3D array of data to be transformed. If X is declared as a 3D array then M is the second dimension of X.

— Input: INTEGER N

On input: the length of the third dimension of the 3D array of data to be transformed. If X is declared as a 3D array then N is the third dimension of X.

— Input/Output: COMPLEX X(L*M*N)

On input: X contains the L by M by N complex 3D array to be transformed. Element ijk is stored in location i+(j-1)*L+(k-1)*L*M of X.
On output: X contains the transformed sequence.

— Input/Output: COMPLEX COMM(5*(L+M+N)+4)

COMM is a communication array used as temporary store. Note that the amount of store explicitly required here is less than in some versions prior to this release (version 4.1 and older). Some further workspace will be allocated internally; the amount of allocated memory requested will be MAX(L*N+N, L*M + L + M, N).

— Output: INTEGER INFO

On output: INFO is an error indicator. On successful exit, INFO contains 0. If INFO = -i on exit, the i-th argument had an illegal value.

             CALL CFFT3D(-1,L,M,N,X,COMM,INFO)
             DO 30 K = 1, N
               DO 20 J = 1, M
                 DO 10 I = 1, L
                   X(I,J) = X(I,J)*EXP(-0.001D0*REAL(I+J+K))
        10       CONTINUE
        20     CONTINUE
        30   CONTINUE
             CALL CFFT3D(1,L,M,N,X,COMM,INFO)

CFFT3D Routine Documentation

`CFFT3D` Routine Documentation