public static function test()
{
$t = new TestProblem();
$t->define();
$solution = $t->solve();
var_dump($solution);
// X[1] Y[4] Z[5] R[6]
$solution = $t->solveMax();
var_dump($solution);
// X[4] Y[6] Z[10] R[9] sum[29]
}
