About Automatic Data Typing :: Automatic Data Typing (Simulink® Fixed Point™)

About Automatic Data Typing

The Fixed-Point Tool automates the task of specifying fixed-point data types in a Simulink model. The tool collects range data for model objects, either from design minimum and maximum values that objects specify explicitly, from logged minimum and maximum values that occur during simulation, or from minimum and maximum values derived using range analysis. Based on these values, the tool proposes fixed-point data types that maximize precision and cover the range. The tool allows you to review the data type proposals and then apply them selectively to objects in your model.

You can use the Fixed-Point Tool to select data types automatically for your model using the following methods.

Automatic Data Typing Method	Advantages	Disadvantages
Using simulation minimum and maximum values	Useful if you know the inputs to use for the model. You do not need to specify any design range information.	Not always feasible to collect full simulation range. Simulation might take a very long time.
Using design minimum and maximum values	You can use this method if the model contains blocks that range analysis does not support. However, if possible, use simulation data to propose data types.	Design range often available only on some input and output signals. Can propose data types only for signals with specified design minimum and maximum values.
Using derived minimum and maximum values	You do not have to simulate multiple times to ensure that simulation data covers the full intended operating range.	Derivation might take a very long time.

Automatic Data Typing Method

Advantages

Disadvantages

Using simulation minimum and maximum values

Useful if you know the inputs to use for the model.
You do not need to specify any design range information.

Not always feasible to collect full simulation range.
Simulation might take a very long time.

Using design minimum and maximum values

You can use this method if the model contains blocks that range analysis does not support. However, if possible, use simulation data to propose data types.

Design range often available only on some input and output signals.
Can propose data types only for signals with specified design minimum and maximum values.

Using derived minimum and maximum values

You do not have to simulate multiple times to ensure that simulation data covers the full intended operating range.