gistfile1.txt

<?php

$a = array(
    0 => array(
        0=>21,
        1=>44,
        2=>35
    ),
    1 => array(
        0=>43,
        1=>78,
        2=>78,
    ),
    2 => array(
        0=>12,
        1=>532,
        2=>46,
    ),
);
$summa = array();
for($i=0; $i < count($a); $i++){
    $buffer = 0;
    for($j=0; $j < count($a[$i]); $j++){
//        $buffer = $buffer + $a[$j][$i]; // =
        $buffer = $buffer + $a[$i][$j]; // | |
    }
    $summa[$i] = $buffer;
}
var_dump($summa);
echo "<br>";

$a = array(
    0 => array(
        0=>21,
        1=>44,
        2=>35
    ),
    1 => array(
        0=>43,
        1=>78,
        2=>78,
    ),
    2 => array(
        0=>12,
        1=>532,
        2=>46,
    ),
);
$sum = array();
$i=0;
while($i < count($a)){
    $buffer = 0;
    $j=0;
    while($j < count($a[$j])){
        $buffer = $buffer + $a[$i][$j];
        $j++;
    }
    $i++;
    $sum[$i] = $buffer;
}
var_dump($sum);
echo "<br>";
$a = array(
    array(
        0=>21,
        1=>44,
        2=>35,
    ),

     array(
        0=>43,
        1=>78,
        2=>78,
    ),
    array(
        0=>12,
        1=>532,
        2=>46,
    ),
);
$suma=array();

foreach($a as $item){
    $bu = 0;
 foreach($item as $item2){
     $bu = $bu + $item2;
     }
    $suma[] = $bu;
}
var_dump($suma);