CSA1S - cubic spline approximation, simple entry for one-dimensional input

       To use CSA1S, load the NCAR Graphics library ngmath.

       Copyright (C) 2000
       University Corporation for Atmospheric Research

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

UNIX                                              January 1999                                     CSA1S(3NCARG)

       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 dimensioned for NI containing the X  coordinates  of  the  input  data
                   points.

       YI          (real,  input) An array dimensioned for NI containing function values at the input XI values,
                   that is, YI(L) is the value of the input function at XI(L) for L=1,NI.

       KNOTS       (integer, input) The number of knots to be used in  constructing  the  approximation  spline.
                   KNOTS  must be at least 4.  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 values to be calculated for the output curve.

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

       YO          (real, output) An array dimensioned for NO containing the calculated function values for  the
                   output curve.

       NWRK        (integer, input) The size of the WORK array.  NWRK must be at least KNOTS*(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.

       CSA1S - cubic spline approximation, simple entry for one-dimensional input

       csagrid, csa1xs, csa1ls, csa1lxs

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

       CALL CSA1S (NI, XI, YI, KNOTS, NO, XO, YO, NWRK, WORK, IER)

       CSA1S is called to find an approximating cubic spline for one-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 CSA1XS.