値をランダムに分配するにはどうすればいいのか ref: http://qiita.com/khsk/items/4dde8384832a405e6e5d

distribute.php

$target = array(
    'A',
    'B',
    'C',
    'D',
    'E',
    'F',
    'G',
    'H',
);

$target_cnt = count($target);
$total = 123456789;
echo $total . "\n";
$result = array_fill(0, $target_cnt, 0);
$i = 0;

while ($total) {
    if (!($i %= $target_cnt)) {
        shuffle($result);
    }
    $rand = mt_rand(0, $total);
    $result[$i] += $rand;
    $total -= $rand;
    $i++;
}

var_dump(array_combine($target, $result));
echo $total . "\n";
echo array_sum($result) . "\n";

distribute2.php

$target = array(
    'A',
    'B',
    'C',
    'D',
    'E',
    'F',
    'G',
    'H',
);

$target_cnt = count($target);
$total = 123456789;
echo $total . "\n";
$result = array_fill(0, $target_cnt, 0);
$remainder = 0; // IDE警告消し
while ($total) {

    $remainder = $total % $target_cnt;
    $quotient = (int)($total / $target_cnt);
    if ($quotient == 0) {
        break;
    }

    for ($i = 0; $i < $target_cnt; $i++) {
        $rand = mt_rand(0, $quotient);
        $result[$i] += $rand;
        $total -= $rand;
    }
}

// 余りの分配
$total -= $remainder;
$i = 0;
while ($remainder--) {
    $i %= $target_cnt;
    $result[$i++]++;
}

var_dump(array_combine($target, $result));
echo $total . "\n";
echo array_sum($result) . "\n";

output

123456789
array(8) {
  ["A"]=>
  int(95557576)
  ["B"]=>
  int(313427)
  ["C"]=>
  int(2720550)
  ["D"]=>
  int(448420)
  ["E"]=>
  int(3296615)
  ["F"]=>
  int(73736)
  ["G"]=>
  int(172534)
  ["H"]=>
  int(20873931)
}
0
123456789

output2

123456789
array(8) {
  ["A"]=>
  int(11087871)
  ["B"]=>
  int(13496825)
  ["C"]=>
  int(15902076)
  ["D"]=>
  int(17920329)
  ["E"]=>
  int(17281928)
  ["F"]=>
  int(21869953)
  ["G"]=>
  int(13350973)
  ["H"]=>
  int(12546834)
}
0
123456789