The original projection data was greatly over-sampled, taking over 20,000 samples in 400 picoseconds for each of the 360 angles. In order to reduce computation time, we uniformly reduced the number of samples and the number of angles. Our shrinkPR code takes the original PR matrix, a matrix whose columns are the projections, and outputs a smaller PR matrix with fewer samples and angles. It also creates a column vector, theta, which contains the angles of the corresponding projections.