#!/usr/bin/perl
use strict;
use warnings;
use PDL;
use PDL::Matrix;

# example: 2x + 3y + 4 = z, plug in known exact values; make sure my coefficients end up 2,3,4

my $matrix_A = mpdl [
    [1,1,1],
    [3,7,1],
    [5,1,1],
    [1,5,1],
];

print "A => ", $matrix_A;
print "B => ", my $column_B = vpdl [9,31,17,21];
print "X => ", my $coeff_X = (($matrix_A->transpose x $matrix_A)->inv x $matrix_A->transpose) x $column_B;