Description:
This subroutine re-orders and normalises the supplied array of Fourier coefficients (as
produced by FFTPACK subroutine PDA_CFFTF) so that the returned arrays looks like the equivalent
arrays returned by NAG routine C06FCF.
The real and imaginary coefficients produced by PDA_CFFTF are numerically larger than the
corresponding C06FCF coefficients by a factor of SQRT(NP), and are stored differently. NAG uses two
separate one-dimensional arrays to store the real and imaginary coefficients, whereas FFTPACK
stored them in a single two dimensional array (each row holds a pair of corresponding real and
imaginary coefficients).
Invocation
CALL PDA_C2NAG( NP, R, X, Y )
Arguments
NP =
INTEGER (Given)
The number of points in the transform.
R( 2, NP ) = REAL (Given)
The input
coefficients, in FFTPACK format.
X( NP ) = REAL (Returned)
The real coefficients, in
NAG format.
Y( NP ) = REAL (Returned)
The imaginary coefficients, in NAG format.
Implementation Status:
A double precision version PDA_DC2NAG of the routine exists.