getMessage(); } return $returnValue; } private static function getCount(array $array1, array $array2): int { $count = count($array1); if ($count !== count($array2)) { throw new Exception(Functions::NA()); } return $count; } /** * These functions accept only numeric arguments, not even strings which are numeric. * * @param mixed $item */ private static function numericNotString($item): bool { return is_numeric($item) && !is_string($item); } /** * SUMX2MY2. * * @param mixed[] $matrixData1 Matrix #1 * @param mixed[] $matrixData2 Matrix #2 * * @return float|string */ public static function sumXSquaredMinusYSquared($matrixData1, $matrixData2) { try { $array1 = Functions::flattenArray($matrixData1); $array2 = Functions::flattenArray($matrixData2); $count = self::getCount($array1, $array2); $result = 0; for ($i = 0; $i < $count; ++$i) { if (self::numericNotString($array1[$i]) && self::numericNotString($array2[$i])) { $result += ($array1[$i] * $array1[$i]) - ($array2[$i] * $array2[$i]); } } } catch (Exception $e) { return $e->getMessage(); } return $result; } /** * SUMX2PY2. * * @param mixed[] $matrixData1 Matrix #1 * @param mixed[] $matrixData2 Matrix #2 * * @return float|string */ public static function sumXSquaredPlusYSquared($matrixData1, $matrixData2) { try { $array1 = Functions::flattenArray($matrixData1); $array2 = Functions::flattenArray($matrixData2); $count = self::getCount($array1, $array2); $result = 0; for ($i = 0; $i < $count; ++$i) { if (self::numericNotString($array1[$i]) && self::numericNotString($array2[$i])) { $result += ($array1[$i] * $array1[$i]) + ($array2[$i] * $array2[$i]); } } } catch (Exception $e) { return $e->getMessage(); } return $result; } /** * SUMXMY2. * * @param mixed[] $matrixData1 Matrix #1 * @param mixed[] $matrixData2 Matrix #2 * * @return float|string */ public static function sumXMinusYSquared($matrixData1, $matrixData2) { try { $array1 = Functions::flattenArray($matrixData1); $array2 = Functions::flattenArray($matrixData2); $count = self::getCount($array1, $array2); $result = 0; for ($i = 0; $i < $count; ++$i) { if (self::numericNotString($array1[$i]) && self::numericNotString($array2[$i])) { $result += ($array1[$i] - $array2[$i]) * ($array1[$i] - $array2[$i]); } } } catch (Exception $e) { return $e->getMessage(); } return $result; } }