/**
* Multiply Matrices
*
* This function will multiply the current matrix with the matrix provided.
* If current Matrix is denoted by 'A' and the inputted is denoted by 'B',
* When written, this will return AB.
*
* @link http://en.wikipedia.org/wiki/Matrix_multiplication
* @param Matrix $bMatrix The matrix to multiply with the current
* @return Matrix The result of multiplication.
* @throws \Exception $msg explains why operation failed
*/
public function mpMatrix(Matrix $bMatrix)
{
if (!$this->_verify() || !$bMatrix->_verify()) {
$eM1 = $this->toString();
$eM2 = $bMatrix->toString();
throw new \Exception("Either '{$eM1}' and/or '{$eM2}' is not a valid Matrix", Matrix::E_INVALID_MATRIX);
}
$aArray = $this->matrix;
$bArray = $bMatrix->getArray();
//The number of columns in A must match the number of rows in B
if (count($aArray[0]) != count($bArray)) {
$mA = $this->toString();
$mB = $bMatrix->toString();
throw new \Exception("Columns in '{$mA}' don't match Rows of '{$mB}'", Matrix::E_NOT_EQUAL);
}
$rArray = array();
//Loop through rows of Matrix A
for ($i = 0; $i < count($aArray); $i++) {
//Loop through the columns of Matrix B
for ($j = 0; $j < count($bArray[0]); $j++) {
$value = 0;
//loop through the rows of Matrix B
for ($k = 0; $k < count($bArray); $k++) {
$value += $aArray[$i][$k] * $bArray[$k][$j];
}
$rArray[$i][$j] = $value;
}
}
$rMatrix = new Matrix($this->toString($rArray));
return $rMatrix;
}
