matically from the dimensions 
% of the input vector. Alternative, backprojection can be forced with |A' * y|.
% 
% Other examples include LSQR, SA-WLS (includes TOF example), ATP-WLS, EM-PKMA 
% with TV regularization and ADMM with TV. Of these, EM-PKMA and ADMM provide 
% examples on how to use the built-in priors. Prepass functions must be run for 
% the following priors: 
% 
% MRP (|options = computeOffsets(options);|)
% 
% Quadratic prior (|options = computeWeights(options);| and |options = quadWeights