s [forward_project](https://github.com/villekf/OMEGA/blob/master/source/forward_project.m) and [backproject](https://github.com/villekf/OMEGA/blob/master/source/backproject.m) as you like. The example provided uses them the same way as in OSEM, but as they simply implement the operations </span><span style=' font-style: italic;'>y = Ax</span><span> and</span><span style=' font-style: italic;'> x = A^Tb</span><span>, respectively, you can implement any algorithm that uses these matrix-vector operations. An e