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.TH CSA3LS 3NCARG "January 1999" UNIX "NCAR GRAPHICS"
.SH NAME
CSA3LS - cubic spline approximation, simple entry for three-dimensional input,
list output
.SH SYNOPSIS
CALL CSA3LS (NI, XI, UI, KNOTS, NO, XO, YO, ZO, UO, 
.br
             NWRK, WORK, IER)
.SH DESCRIPTION
.IP NI 12
(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.
.IP XI 12
(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(3,L) is the Z coordinate 
for the input domain for L=1,NI.
.IP UI 12
(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.
.IP KNOTS 12
(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.
.IP NO 12
(integer, input) The number of coordinate values in the output list.
NO can be any positive number.
.IP XO 12
(real, input) An array dimensioned for NO containing the X coordinates
of the output list.
.IP YO 12
(real, input) An array dimensioned for NO containing the Y coordinates
of the output list.
.IP ZO 12
(real, input) An array dimensioned for NO containing the Z coordinates
of the output list.
.IP UO 12
(real, output) An array dimensioned for NO containing the calculated
function values for the output spline.  UO(I) is the calculated functional
value at (XO(I),YO(I),ZO(I)) for I=1,NO.
.IP NWRK 12 
(integer, input) The size of the WORK array.  NWRK must be at least
NK * (NK+3) where NK = KNOTS(1) * KNOTS(2) * KNOTS(3).
.IP WORK 12
(real, input) A work array dimensioned for NWRK.
.IP IER 12
(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.
.SH USAGE
CSA3LS 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 CSA3LXS. 
.SH ACCESS
To use CSA3LS, load the NCAR Graphics library ngmath.
.SH SEE ALSO
csagrid,
csa3s,
csa3xs,
csa3lxs
.sp
Complete documentation for Csagrid is available at URL
.br
http://ngwww.ucar.edu/ngdoc/ng/ngmath/csagrid/csahome.html
.SH COPYRIGHT
Copyright (C) 2000
.br
University Corporation for Atmospheric Research
.br

The use of this Software is governed by a License Agreement.