Data commit

Task/Polynomial-regression/Perl/polynomial-regression-1.pl

@@ -0,0 +1,14 @@
+use strict;
+use warnings;
+use Statistics::Regression;
+
+my @x = <0 1 2 3 4 5 6 7 8 9 10>;
+my @y = <1 6 17 34 57 86 121 162 209 262 321>;
+
+my @model = ('const', 'X', 'X**2');
+
+my $reg = Statistics::Regression->new( '', [@model] );
+$reg->include( $y[$_], [ 1.0, $x[$_], $x[$_]**2 ]) for 0..@y-1;
+my @coeff = $reg->theta();
+
+printf "%-6s %8.3f\n", $model[$_], $coeff[$_] for 0..@model-1;

Task/Polynomial-regression/Perl/polynomial-regression-2.pl

@@ -0,0 +1,25 @@
+#!/usr/bin/perl -w
+use strict;
+
+use PDL;
+use PDL::Math;
+use PDL::Fit::Polynomial;
+
+my $x = float [0,  1,  2,  3,  4,  5,  6,   7,   8,   9,   10];
+my $y = float [1,  6,  17, 34, 57, 86, 121, 162, 209, 262, 321];
+# above will output:  3.00000037788248 * $x**2 + 1.99999750988868 * $x + 1.00000180493936
+
+# $x = float [ 0,   1,   2,    3,    4,    5,    6,     7,     8,     9];
+# $y = float [ 2.7, 2.8, 31.4, 38.1, 58.0, 76.2, 100.5, 130.0, 149.3, 180.0];
+# above correctly returns: " 1.08484845125187 * $x**2 + 10.3551513321297 * $x-0.616363852007752 "
+
+my ($yfit, $coeffs) = fitpoly1d $x, $y, 3;      # 3rd degree
+
+foreach (reverse(0..$coeffs->dim(0)-1)) {
+  print " +" unless(($coeffs->at($_) <0) || $_==$coeffs->dim(0)-1); # let the unary minus replace the + operator
+  print " ";
+  print $coeffs->at($_);
+  print " * \$x" if($_);
+  print "**$_" if($_>1);
+  print "\n" unless($_)
+}