HP MLIB User's Guide Vol. 2 7th Ed.

550 HP MLIB User’s Guide
S2DFFT/D2DFFT Two-dimensional FFT
INTEGER*8 l1, l2, ldxy, iopt, ier
REAL*8 x(ldxy, l2), y(ldxy, l2)
CALL D2DFFT(x, y, l1, l2, ldxy, iopt, ier)
INTEGER*8 l1, l2, ldxy, iopt, ier
REAL*4 x(ldxy, l2), y(ldxy, l2)
CALL S2DFFT(x, y, l1, l2, ldxy, iopt, ier)
Input x Array of real parts of the data to be transformed.
y Array of imaginary parts of the data to be transformed.
l1 Number of rows of data, l1 > 0.
l2 Number of columns of data, l2 > 0.
ldxy The leading dimension of arrays x and y, with ldxy ≥ l1.
iopt Option flag:
iopt ≥ 0 Compute forward transform.
iopt < 0 Compute inverse transform.
Output x and y The transformed data replaces the input if ier = 0 is
returned.
ier Status response:
ier = 0 Normal return—transform successful.
ier = −1 l1 ≤ 0.
ier = −2 l2 ≤ 0.
ier = −3 ldxy < l1.
ier ≤−4 Probable error in ldxy or dimensions
of x and y.