CSA3S - cubic spline approximation, simple entry for
three-dimensional input
CALL CSA3S (NI, XI, UI, KNOTS, NXO, NYO, NZO, XO, YO, ZO,
UO, NWRK, WORK, IER)
- NI
- (integer,input) The number of input data points. It must be that NI .gt. 3
and, depending on the size of KNOTS below, NI may have to be larger.
- XI
- (real, input) An array containing the X - Y - Z coordinates of the input
data points. XI is dimensioned for 3 x NI. XI(1,L) is the X coordinate,
XI(2,L) is the Y coordinate, and XI(2,L) is the Z coordinate for the input
domain for L=1,NI.
- UI
- (real, input) An array dimensioned for NI containing function values at
the input XI values, that is, UI(L) is the value of the input function at
XI(L) for L=1,NI.
- KNOTS
- (integer, input) An array dimensioned for 3 containing the number of knots
to be used in each coordinate direction for constructing the approximation
spline. KNOTS(I) must be at least 4 for I=1,3. The larger the value for
KNOTS, the closer the approximated curve will come to passing through the
input function values.
- NXO
- (integer, input) The number of X coordinate values in the output
grid.
- NYO
- (integer, input) The number of Y coordinate values in the output
grid.
- NZO
- (integer, input) The number of Z coordinate values in the output
grid.
- XO
- (real, input) An array dimensioned for NXO containing the X coordinates of
the output surface.
- YO
- (real, input) An array dimensioned for NYO containing the Y coordinates of
the output surface.
- ZO
- (real, input) An array dimensioned for NZO containing the Y coordinates of
the output surface.
- UO
- (real, output) An array dimensioned for NXO x NYO x NZO containing the
calculated function values for the output function. UO(I,J,K) is the
calculated functional value at (XO(I), YO(J), ZO(K)) for I=1,NXO and
J=1,NYO and K=1,NZO.
- NWRK
- (integer, input) The size of the WORK array. NWRK must be at least NK *
(NK+3) where NK = KNOTS(1) * KNOTS(2) * KNOTS(3).
- WORK
- (real, input) A work array dimensioned for NWRK.
- IER
- (integer, output) An error return value. If IER is returned as 0, then no
errors were detected. If IER is non-zero, then refer to the man page for
csagrid_errors for details.
CSA3S is called to find an approximating cubic spline for
three-dimensional input data. If you want to weight the input data values,
calculate derivatives, or handle data sparse areas specially, then you will
need to use CSA3S.
To use CSA3XS, load the NCAR Graphics library ngmath.
csagrid, csa3xs, csa3ls, csa3lxs
Complete documentation for Csagrid is available at URL
http://ngwww.ucar.edu/ngdoc/ng/ngmath/csagrid/csahome.html
Copyright (C) 2000
University Corporation for Atmospheric Research
The use of this Software is governed by a License Agreement.