fun getBaseMatrix(): SimpleMatrix
Returns the underlying matrix object from the back-end this Matrix is wrapping. This should be used sparingly (as it breaks encapsulation), but it can increase performance by using computation specifically designed for a particular back-end. Code using this method should not rely on a particular back-end, and should always fallback to slow generic code if an unrecognized matrix is returned here (e.g. use get and set) to access the elements generically).