public function define()
{
$p = ProblemFactory::newProblem("Test");
$x = $p->variable('X', 1, 10);
$y = $p->variable('Y', 1, 10);
$z = $p->variable('Z', 1, 10);
$r = $p->variable('R', 1, 10);
$vars = array($x, $y, $z, $r);
$p->post($x, '<', $y);
$p->post($z, '>', 4);
$p->post($x->plus($y), '=', $z);
$p->postAllDifferent($vars);
$coef1 = array(3, 4, -5, 2);
$p->post($coef1, $vars, '>', 0);
$p->post($vars, '>=', 15);
$coef2 = array(2, -4, 5, 1);
$p->post($coef2, $vars, '>', $x->multiply($y));
$this->problem = $p;
$this->data = $vars;
}