MCordingley\LinearAlgebra\Matrix::adjugate PHP Method

    public function adjugate() : self
    {
        $this->checkSquare();
        return $this->inverse()->multiplyScalar($this->determinant());
    }

 public function testAdjugate()
 {
     $matrix = new Matrix([[1, -1, 2], [4, 0, 6], [0, 1, -1]]);
     $adjoint = $matrix->adjugate();
     static::assertEquals(-6, $adjoint->get(0, 0));
     static::assertEquals(1, $adjoint->get(0, 1));
     static::assertEquals(-6, $adjoint->get(0, 2));
     static::assertEquals(4, $adjoint->get(1, 0));
     static::assertEquals(-1, $adjoint->get(1, 1));
     static::assertEquals(2, $adjoint->get(1, 2));
     static::assertEquals(4, $adjoint->get(2, 0));
     static::assertEquals(-1, $adjoint->get(2, 1));
     static::assertEquals(4, $adjoint->get(2, 2));
 }