/**
* Tests LinAlg::lud with singular 4x4 matrix
*/
public function testLUDecompositionSingularMatrix()
{
$matrix = NumPHP::identity(4);
$matrix->set(2, 2, 0);
$expectedP = NumPHP::identity(4);
$expectedL = NumPHP::identity(4);
$expectedU = NumPHP::identity(4);
$expectedU->set(2, 2, 0);
list($pMatrix, $lMatrix, $uMatrix) = LinAlg::lud($matrix);
$this->assertNumArrayEquals($expectedP, $pMatrix, 'Matrix P is not equal');
$this->assertNumArrayEquals($expectedL, $lMatrix, 'Matrix L is not equal');
$this->assertNumArrayEquals($expectedU, $uMatrix, 'Matrix U is not equal');
}
/**
* Tests if InvalidArgumentException will be thrown, when using LinAlg::solve with not align matrix and vector
*
* @expectedException \NumPHP\LinAlg\Exception\InvalidArgumentException
* @expectedExceptionMessage Can not solve a linear system with matrix (4, 4) and matrix (3)
*/
public function testSolveNotAlign()
{
$matrix = NumPHP::identity(4);
$vector = NumPHP::ones(3);
LinAlg::solve($matrix, $vector);
}
/**
* Tests if Helper::isNotSingularMatrix works with invalid not singular matrix
*/
public function testCheckNotSingularMatrixInvalid()
{
$numArray = NumPHP::identity(4);
$numArray->set(2, 2, 0);
$this->assertFalse(Helper::isNotSingularMatrix($numArray));
}
/**
* Tests NumPHP::identity with argument 3
*/
public function testIdentity()
{
$numArray = NumPHP::identity(3);
$expectedNumArray = NumPHP::eye(3, 3);
$this->assertNumArrayEquals($expectedNumArray, $numArray);
}
/**
* Calculates the inverse of a not singular square matrix
*
* @param mixed $squareMatrix not singular matrix
*
* @throws SingularMatrixException will be thrown, when `$squareMatrix` is singular
*
* @api
* @since 1.0.0
*
* @return NumArray
*/
public static function inv($squareMatrix)
{
if (!$squareMatrix instanceof NumArray) {
$squareMatrix = new NumArray($squareMatrix);
} elseif ($squareMatrix->inCache(self::CACHE_KEY_INVERSE)) {
return $squareMatrix->getCache(self::CACHE_KEY_INVERSE);
}
if (!Helper::isNotSingularMatrix($squareMatrix)) {
throw new SingularMatrixException("Matrix is singular");
}
$shape = $squareMatrix->getShape();
$inv = self::solve($squareMatrix, NumPHP::identity($shape[0]));
$squareMatrix->setCache(self::CACHE_KEY_INVERSE, $inv);
return self::inv($squareMatrix);
}
