Abstract: Method for ordering computer software procedures in an order using a computing machine for modeling each of multiple blocks of a block diagram. The block diagram is capable of having at least one feedback loop. Each block corresponds to a software procedure for performing at least one function and has at least one input or at least one output. The block diagram has interconnections between such inputs and outputs of such blocks forming a block diagram. A list of inputs for each of such blocks is generated; a list of outputs for each of such blocks is generated; a feed-through list for each of at least some of such outputs of such blocks is generated. Each feed-through list has a list of any input which directly affects the output of the same block. The input, output and feed-through lists are machine processed for ordering of such procedures in the order during modeling.