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.