m</span></a><span>, the second method is the old one using functions.</span></div><h3  class = 'S6' id = 'H_E8C79E6D' ><span>Class based examples</span></h3><div  class = 'S1'><span>First is a class-based exampled computing OSEM/MLEM estimates (line 821) with the use of the special forward and backward projection operators. The major steps needed for class based use is the creation of the class object with </span><span style=' font-family: monospace;'>forwardBackwardProject(options)</span><span> and the loa