title: How do I combine transforms in the ceres solver?
body: <p>I have two parameters transformations as input to my Ceres cost function. They are both transforms that are to be combined, in order to reproject my points. Both transforms are given in the form of a Rodrigues rotation vector, and a translation vector.</p>
  
  <p>My question is, how do I combine these two transforms within the cost function (using Ceres API's), in order to reproject the points?</p>