/**
* @inheritDoc
*/
public function derive(NumericMatrix $mA, $extra = null)
{
if ($mA->is('empty')) {
return TypeFactory::createInt(0);
}
if ($mA->is('singleitem')) {
return $mA->get(1, 1);
}
$calc = new Calculator();
return array_reduce($mA->toArray(), function ($c1, $row) use($calc) {
return array_reduce($row, function ($carry, $item) use($calc) {
return $calc->add($item, $carry);
}, $c1);
}, TypeFactory::createInt(0));
}
/**
* Find tr(M)
*
* @param NumericMatrix $mA
* @param mixed $extra
* @return numeric
*
* @throws Chippyash/Math/Matrix/Exceptions/UndefinedComputationException
*/
public function derive(NumericMatrix $mA, $extra = null)
{
if ($mA->is('singleitem')) {
return $mA->get(1, 1);
}
$this->assertMatrixIsNotEmpty($mA, 'No trace for empty matrix')->assertMatrixIsSquare($mA, 'No trace for non-square matrix');
$tr = new FloatType(0);
$size = $mA->rows();
$data = $mA->toArray();
$calc = new Calculator();
for ($x = 0; $x < $size; $x++) {
$tr = $calc->add($tr, $data[$x][$x]);
}
return $tr;
}
/**
* Return determinant of a 2X2 matrix
* @link http://en.wikipedia.org/wiki/Matrix_determinant#2.C2.A0.C3.97.C2.A02_matrices
* [[a, b]
* [c, d]]
* ad - bc
*
* @param \Chippyash\Math\Matrix\NumericMatrix $mA
*/
protected function det2(NumericMatrix $mA)
{
$c = $this->calc();
return $c->sub($c->mul($mA->get(1, 1), $mA->get(2, 2)), $c->mul($mA->get(1, 2), $mA->get(2, 1)));
}
