title: How to convert GpuMat to CvMat in OpenCV?
body: <p>I know how to do the opposite i.e. get <code>GpuMat</code> from <code>CvMat</code> using upload, but I need a <code>CvMat</code> from <code>GpuMat</code>, is there any method that can be used for this?</p>