NAME

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

SYNOPSIS

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

DESCRIPTION

       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(3,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.

       NO          (integer, input) The number of coordinate values in the output list.  NO can be any  positive
                   number.

       XO          (real, input) An array dimensioned for NO containing the X coordinates of the output list.

       YO          (real, input) An array dimensioned for NO containing the Y coordinates of the output list.

       ZO          (real, input) An array dimensioned for NO containing the Z coordinates of the output list.

       UO          (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.

       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.

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.

ACCESS

       To use CSA3LS, load the NCAR Graphics library ngmath.

SEE ALSO

       csagrid, csa3s, csa3xs, csa3lxs

       Complete documentation for Csagrid is available at URL
       http://ngwww.ucar.edu/ngdoc/ng/ngmath/csagrid/csahome.html

COPYRIGHT

       Copyright (C) 2000
       University Corporation for Atmospheric Research

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