PDA_C2NAG - Convert FFTPACK complex Fourier transform array into equivalent NAG arrays

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.