|
public static arraySizeNotMatch ( ) : |
||
| return | ||
/**
* @param array $samples
* @param array $targets
*
* @throws InvalidArgumentException
*/
public function __construct(array $samples, array $targets)
{
if (count($samples) != count($targets)) {
throw InvalidArgumentException::arraySizeNotMatch();
}
$this->samples = $samples;
$this->targets = $targets;
}
/**
* @param array $a
* @param array $b
*
* @return float
*
* @throws InvalidArgumentException
*/
public function distance(array $a, array $b) : float
{
if (count($a) !== count($b)) {
throw InvalidArgumentException::arraySizeNotMatch();
}
$distance = 0;
$count = count($a);
for ($i = 0; $i < $count; ++$i) {
$distance += abs($a[$i] - $b[$i]);
}
return $distance;
}
/**
* @param array $actualLabels
* @param array $predictedLabels
* @param bool $normalize
*
* @return float|int
*
* @throws InvalidArgumentException
*/
public static function score(array $actualLabels, array $predictedLabels, bool $normalize = true)
{
if (count($actualLabels) != count($predictedLabels)) {
throw InvalidArgumentException::arraySizeNotMatch();
}
$score = 0;
foreach ($actualLabels as $index => $label) {
if ($label == $predictedLabels[$index]) {
++$score;
}
}
if ($normalize) {
$score = $score / count($actualLabels);
}
return $score;
}
/**
* @param array|int[]|float[] $x
* @param array|int[]|float[] $y
*
* @return float
*
* @throws InvalidArgumentException
*/
public static function pearson(array $x, array $y)
{
if (count($x) !== count($y)) {
throw InvalidArgumentException::arraySizeNotMatch();
}
$count = count($x);
$meanX = Mean::arithmetic($x);
$meanY = Mean::arithmetic($y);
$axb = 0;
$a2 = 0;
$b2 = 0;
for ($i = 0; $i < $count; ++$i) {
$a = $x[$i] - $meanX;
$b = $y[$i] - $meanY;
$axb = $axb + $a * $b;
$a2 = $a2 + pow($a, 2);
$b2 = $b2 + pow($b, 2);
}
$corr = $axb / sqrt((double) ($a2 * $b2));
return $corr;
}
