I don't like that we are repeating code here - lets do one of two things here:
1. Make the conversions into private class methods and call them in the switch case
or
2. Provide a default value in the method signature for `option`

eg.

```cpp
template <typename T> cv::Mat SG2CVMatFactory::getMatrix(CDenseFeatures<float64_t>* A, SG2CVOptions option = SG2CV_MEMCPY)
```