A BLOCK DIAGRAM SIMULATOR

An apparatus and/or method (FIG. 1) using an automatic program generation computer (10) for generation of a computer (output of 46 or 48) which represents a functional system (FIG. 3) on a display (FIG. 1A) (3 of FIG. 1A). A system has a plurality of interactively connected functionality blocks (FIG. 3 - 64, 68, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90) which form a block diagram (FIG. 3) and typically, the block diagram (FIG. 3) has one or more feedback loops (FIG. 3 - 92, 104, 120, 106, 100). Each of the blocks has at least one input (I1), at least some of the blocks have at least one input functionally defined by and connected to at least one of the outputs (O1). At least one of the blocks is a state block (FIG. 3 - 80, 84) whose operation at one time is dependent on the condition of at least one input (I1) for the state block (FIG. 3 - 80, 84) at a prior time. A stored update state procedure (14a) is provided corresponding to the state block (FIG. 3 - 80, 84) defining the state as a function of at least one of the inputs to the state block (FIG. 3 - 80, 84). At least one stored update output procedure (14a) is provided and corresponds to each of the blocks for defining at least one of the outputs (O1) of a block. The output of the update output procedure is a function of at least one of the inputs of a block and/or the state of a block.