NAME
    Math::Approx

METHODS
  new (constructor)
        Math::Approx->new(\&poly, $degree, %data);

    If the first argument to the constructor is a CODE reference, this is
    used as the function to iterate over the data. Such a function must take
    two arguments: The *degree* and the *x* value.

    For interpolation with plain polynomials *poly* can be defined as:

            sub poly {
                my($n,$x) = @_;
                return $x ** $n;
            }

    If the first argument in the constructor is a FALSE value instead of a
    CODE reference, then the above plain polynomial *poly* is used as the
    iterator function.

    The second argument is the maximum degree which should be used for
    interpolation. Degrees start with 0.

    The rest of the arguments are treated as pairs of x and y samples which
    should be approximated.

    The constructor returns a Math::Approx reference.

  approx
            $approximation->approx(17);

    The method returns the approximated y value for the x value given as
    argument.

  fit
            $approximation->fit;

    Returns the medim square error for the data points.

  plot
            $approximation->plot("tmp/app");

    Prints all data pairs and the corresponding approximation pairs into the
    filename given as argument. The output is suitable for usage with
    gnuplot(1).

  print
            $approximation->print;

    Prints information about the approximation on *STDOUT*

EXAMPLE
            use Math::Approx;
        
            sub poly {
                my($n,$x) = @_;
                return $x ** $n;
            }
        
            for (1..20) {
                $x{$_} = sin($_/10)*cos($_/30)+0.3*rand;
            }
        
            $a = new Math::Approx (\&poly, 5, %x);
            $a->print;
            $a->plot("math-approx-demo.out");
            print "Fit: ", $a->fit, "\n";

SEE ALSO
    gnuplot(1).

AUTHOR
    Ulrich Pfeifer <pfeifer@wait.de>

