#!/usr/bin/perl

use strict;
use warnings;
use Algorithm::CurveFit;

my @X_data = qw(-20 -19 -18 -17 -16 -15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14);
my @Y_data = qw(1212 1095 984 879 780 687 600 519 444 375 312 255 204 159 120 87 60 39 24 15 12 15 24 39 60 87 120 159 204 255 312 375 444 519 600);
my $variable = 'x';
my $equation = 'r + m * x^2';
my @parameters = (
    ['r', '100'],
    ['m', '1'],
);
my $maxiter = '200';
my $square_residual = Algorithm::CurveFit->curve_fit(
    formula            => $equation, # may be a Math::Symbolic tree instead
    params             => \@parameters,
    variable           => $variable,
    xdata              => \@X_data,
    ydata              => \@Y_data,
    maximum_iterations => $maxiter,
);

print "$parameters[0][1] (should be 12)\t$parameters[1][1] (should be 3)\n";