NAME

       c_csa1s - cubic spline approximation, simple entry for one-dimensional input

FUNCTION PROTOTYPE

       float *c_csa1s(int, float [], float [], int, int, float [], int *);

SYNOPSIS

       float *c_csa1s(int n, float xi[], float yi[], int knots,
                   int m, float xo[], int *ier);

DESCRIPTION

       n           (integer,input)  The number of input data points. It must be that n is greater
                   than 3 and, depending on the size of knots below, n may have to be larger.

       xi          (real, input) An array dimensioned for n  containing  the  abscissae  for  the
                   input function.

       yi          (real,  input)  An array dimensioned for n containing the functional values of
                   the input function -- yi[k] is the functional value at xi[k] for k=0,n-1.

       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.

       m           (integer, input) The number of values to be calculated for the output curve.

       xo          (real,  input)  An array dimensioned for m containing the X coordinates of the
                   output curve.

       ier         (pointer to 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 error
                   list in the error table for details.

USAGE

       c_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 c_csa1xs.

       c_csa1s returns a pointer to a linear array of data that is the approximated curve.

ACCESS

       To use c_csa1s, load the NCAR Graphics library ngmath.

SEE ALSO

       csagrid, c_csa1xs, c_csa1ls, c_csa1lxs

       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.