1CSA3LS(3NCARG)                   NCAR GRAPHICS                  CSA3LS(3NCARG)
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NAME

6       CSA3LS - cubic spline approximation, simple entry for three-dimensional
7       input, list output
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SYNOPSIS

10       CALL CSA3LS (NI, XI, UI, KNOTS, NO, XO, YO, ZO, UO,
11                    NWRK, WORK, IER)
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DESCRIPTION

14       NI          (integer,input) The number of input data points. It must be
15                   that  NI  .gt. 3 and, depending on the size of KNOTS below,
16                   NI may have to be larger.
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18       XI          (real, input) An array containing the X - Y - Z coordinates
19                   of  the  input  data points.  XI is dimensioned for 3 x NI.
20                   XI(1,L) is the X coordinate, XI(2,L) is the  Y  coordinate,
21                   and  XI(3,L)  is  the Z coordinate for the input domain for
22                   L=1,NI.
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24       UI          (real, input) An array dimensioned for NI containing  func‐
25                   tion  values  at the input XI values, that is, UI(L) is the
26                   value of the input function at XI(L) for L=1,NI.
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28       KNOTS       (integer, input) An array dimensioned for 3 containing  the
29                   number of knots to be used in each coordinate direction for
30                   constructing the approximation spline.  KNOTS(I) must be at
31                   least  4  for  I=1,3.   The larger the value for KNOTS, the
32                   closer the approximated curve will come to passing  through
33                   the input function values.
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35       NO          (integer,  input)  The  number  of coordinate values in the
36                   output list.  NO can be any positive number.
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38       XO          (real, input) An array dimensioned for NO containing the  X
39                   coordinates of the output list.
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41       YO          (real,  input) An array dimensioned for NO containing the Y
42                   coordinates of the output list.
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44       ZO          (real, input) An array dimensioned for NO containing the  Z
45                   coordinates of the output list.
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47       UO          (real,  output)  An array dimensioned for NO containing the
48                   calculated function values for the output spline.  UO(I) is
49                   the  calculated functional value at (XO(I),YO(I),ZO(I)) for
50                   I=1,NO.
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52       NWRK        (integer, input) The size of the WORK array.  NWRK must  be
53                   at  least  NK  *  (NK+3)  where  NK = KNOTS(1) * KNOTS(2) *
54                   KNOTS(3).
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56       WORK        (real, input) A work array dimensioned for NWRK.
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58       IER         (integer,  output)  An  error  return  value.   If  IER  is
59                   returned as 0, then no errors were detected. If IER is non-
60                   zero, then refer to the man  page  for  csagrid_errors  for
61                   details.
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USAGE

64       CSA3LS is called to find an approximating cubic spline for three-dimen‐
65       sional input data.  If you want to weight the input data values, calcu‐
66       late  derivatives, or handle data sparse areas specially, then you will
67       need to use CSA3LXS.
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ACCESS

70       To use CSA3LS, load the NCAR Graphics library ngmath.
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SEE ALSO

73       csagrid, csa3s, csa3xs, csa3lxs
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75       Complete documentation for Csagrid is available at URL
76       http://ngwww.ucar.edu/ngdoc/ng/ngmath/csagrid/csahome.html
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79       Copyright (C) 2000
80       University Corporation for Atmospheric Research
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82       The use of this Software is governed by a License Agreement.
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86UNIX                             January 1999                   CSA3LS(3NCARG)
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