There are times that your app collects a whole lot of data (by capturing it live or by downloading from a third party, or import from email), and you want to do a whole ton of reports and visualisations inside your app. .
To do lots of computing inside your smartphone is a very challenging job, as I have experienced myself in processing video data. A small trick is to use your GPU, which could be 10-100 times faster than your CPU in calculating floating point.
Setting up a GPU shader and calculation could be a huge task for anybody who are not familiar with OpenGL. So, this excellent GPGPU library could help you a lot, all you need to do is to change the calculation inside the vsh file. I am planning to make it even easier for anybody to use in the near future.