spfft1.f File Reference

Perform multiple fast Fourier transforms. More...

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Functions/Subroutines
subroutine	spfft1 (IMAX, INCW, INCG, KMAX, W, G, IDIR)
	This subprogram performs multiple fast Fourier transforms between complex amplitudes in Fourier space and real values in cyclic physical space. More...

Detailed Description

Perform multiple fast Fourier transforms.

Author

Iredell

Date

96-02-20

Definition in file spfft1.f.

Function/Subroutine Documentation

spfft1()

subroutine spfft1	(	integer, intent(in)	IMAX,
		integer, intent(in)	INCW,
		integer, intent(in)	INCG,
		integer, intent(in)	KMAX,
		complex, dimension(incw,kmax), intent(inout)	W,
		real, dimension(incg,kmax), intent(inout)	G,
		integer, intent(in)	IDIR
	)

This subprogram performs multiple fast Fourier transforms between complex amplitudes in Fourier space and real values in cyclic physical space.

Subprogram spfft1() initializes trigonometric data each call. Use subprogram spfft() to save time and initialize once. This version invokes the IBM ESSL FFT.

Note

The restrictions on IMAX are that it must be a multiple of 1 to 25 factors of two, up to 2 factors of three, and up to 1 factor of five, seven and eleven.

This subprogram is thread-safe.

Parameters

	IMAX	number of values in the cyclic physical space (see limitations on imax in remarks below.)
	INCW	first dimension of the complex amplitude array (INCW >= IMAX/2+1)
	INCG	first dimension of the real value array (INCG >= IMAX)
	KMAX	number of transforms to perform
[out]	W	complex amplitudes if IDIR>0
[out]	G	values if IDIR<0
	IDIR	direction flag IDIR>0 to transform from Fourier to physical space IDIR<0 to transform from physical to Fourier space

Author

Iredell

Date

96-02-20

Definition at line 32 of file spfft1.f.

References scrft(), and srcft().