Flow chart for the SPARTA and MORIA codes. Red fields represent codes; blue fields represent data products. From the codes’ perspective, blue arrows signify inputs, whereas red arrows signify outputs. Particle data, the original output from the simulation, are fed into a halo finder to create catalogs. SPARTA needs the halos to be connected between snapshots, that is, it needs progenitor/descendant information. Based on the information in the snapshot and catalog files, SPARTA creates an hdf5 output file. MORIA combines the information in that file with the original halo catalogs to create enhanced catalogs and merger trees. The simulation data (the left-hand side of the schematic) are discussed in Section 2, the SPARTA and MORIA codes in Sections 3 and 4, respectively.