SINQI/SINQF/SINQB

DCL:MATH2:FFTLIB: Fast Fourier Transformation: Explanation of Subroutines

2.3.5 SINQI/SINQF/SINQB

1.

Function

Performs sine transformation only on odd wavenumber components: SINQI initializes; SINQF performs forward sine transformation; and SINQB performs inverse sine transformation.

2.

Definition

Forward transformation is defined as follows:

Inverse transformation is defined as follows:

3.

Call

CALL SINQI(N,WSAVE)
CALL SINQF(N,R,WSAVE)
CALL SINQB(N,R,WSAVE)

4.

Explanation of Parameters

N (I) Length of data to process.

WSAVE (R) Working array. Must have length of at least 3 N+15.

R (R) Floating-point array to process. It is both the input and output parameter. (See above definition.)

5.

Notes

(a): This transformation does not involve normalization. in other words, when SINQF and SINQB are called successively, then the value of the original value multiplied by a factor of 4N is returned.

`N`	`(I)`	Length of data to process.
`WSAVE`	`(R)`	Working array. Must have length of at least 3 `N`+15.
`R`	`(R)`	Floating-point array to process. It is both the input and output parameter. (See above definition.)