Using the data type optimization feature in Fixed-Point Designer™, automatically iterate and choose the smallest heterogenous data types for your model while meeting constraints on the numerical behavior of your system. 

Say you are targeting a 32-bit microcontroller. Do you need 32-bit word length or does 16 bits suffice? Do all your signals or variables need 32 bits? How will you compare the numerical behavior of the quantized model? 

What if your target is an FPGA? You will have to iterate through various combinations of data types for all the elements of your model. 

Data type optimization automates this whole process for you.