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

562 HP MLIB User’s Guide
SFFTS/DFFTS Simultaneous one-dimensional FFT
Output x and y The transformed data replaces the input if ier = 0 is
returned. Unchanged if ier < 0.
ier Status response:
ier = 0 Normal return—transform successful.
ier = −1 l ≤ 0.
ier = −2 incl ≤ 0.
ier
= −3 n ≤ 0.
ier
= −4 incn ≤ 0.
ier = −5 l, incl, n, and incn are incompatible.
Refer to “Notes.”
Notes Typically, x and y will be two- or three-dimensional arrays with each data set
being a one-dimensional section of the arrays, that is, all but one subscript will
be constant within a data set.
If x and y are two-dimensional arrays of dimension ldxy by mdxy, and if the
data sets are stored in the columns of x and y, l ≤ ldxy, n ≤ mdxy, incl = 1, and
incn = ldxy. For example:
CALL SFFTS (x, y, l, 1, n, ldxy, iopt, ier)
If x and y are two-dimensional arrays as above and data sets are stored in rows
of x and y, l ≤ mdxy, n ≤ ldxy, incl = ldxy, and incn = 1. For example:
CALL SFFTS (x, y, l, ldxy, n, 1, iopt, ier)
If x and y are three-dimensional arrays of dimension ldxy by mdxy by ndxy,
then incl and incn will usually be 1, ldxy, or ldxy×mdxy, depending on which of
the subscripts of the three-dimensional array varies within a data set, which
subscript varies between data sets, and which remains constant. Specifically, if
the subscript that varies within a data set is the
1st subscript, use incl = 1.
2nd subscript, use incl = ldxy.
3rd subscript, use incl = ldxy×mdxy.