create mxn matrix

mxn.php

<?php

$i1 = 2; //m
$i2 = 3; //n

//your requirement was that you will add 1 to the incoming data, here $i1 and $i2 - so added 1 with $i1 and $i2 in the loop below
$matrix = array();
for($j=1;$j<=($i1+1);$j++){
	$_row = array_fill(0, ($i2+1), 0);
	array_push($matrix,$_row);
}

print_r($matrix);