A collection of functions for programatically manipulating the structure and connectivity of Simulink models. In Simulink, models can be altered using a collection of built-in function calls (e.g. add_block, add_line) and by modifying block parameters (using set and set_param). Maniuplating these parameters directly is tedious and requires a great deal of error-checking code. These functions make a variety of tasks--adding or removing a block, connecting or disconnecting pairs of blocks, modifying block positions and sizes, etc.--to accomplish via simple function calls. Generally, the most common use of these functions is in a masked subsystem initialization callback. For example, if you design a masked subsystem which has an adjustable number of inputs, when the user changes the number of inputs required, the initialization callback will need to create additional or destroy extra block inports and connect them to their desired destinations within the subsystem.