PDA_NAG2R

Convert NAG Hermitian Fourier transform array into array usable by FFTPACK routine PDA_RFFTB

Description:

This subroutine modifies the supplied array of Fourier coefficients (as produced by NAG subroutine C06FAF) so that an inverse FFT can be performed on them using FFTPACK routine PDA_RFFTB. The resulting inverse will have the same normalisation as the original data transformed using PDA_RFFTF.

Invocation

CALL PDA_NAG2R( NP, R )

Arguments

NP = INTEGER (Given)
The size of the array.
R( NP ) = REAL (Given and Returned)
The array holding the Fourier coefficients. Supplied in NAG format and returned in FFTPACK format.

Implementation Status:

A double precision version PDA_DNAG2R of the routine exists.

Notes:

A call to PDA_R2NAG followed by a call to PDA_NAG2R will result in the original data being divided by NP.

Some speed is sacrificed in order to perform the conversion in-situ.