/**
* Computes the population standard deviation for the numbers
* in this list
* @return string
*/
public function stdDev()
{
Number::setScale(static::NUMERIC_FUNCTIONS_SCALE);
$mean = $this->average();
$squares = new static();
foreach ($this->_Arr as $num) {
$squares->add(Number::pow(Number::sub(\strval($num), $mean), '2'));
}
return Number::sqrt($squares->average());
}
/**
* Converts the set to an integer string. The difference between this
* and toInt() is that this method uses bcmath functions to handle
* large bit sets that would fail to properly be converted to a PHP
* integer if toInt() is used.
* @return string
*/
public function toLongInt()
{
$total = '0';
for ($i = 0, $l = $this->count(); $i < $l; ++$i) {
if ($this->_List[$i]) {
$total = Number::add($total, Number::pow('2', (string) $i));
}
}
return $total;
}
public function testPow()
{
$l = '65';
$r = '21';
$exp = '117809547936177440979200839996337890625';
$this->assertEquals($exp, Number::pow($l, $r));
}
