Comments on: The If-Else Construct in Models

By: Seth

Seth — Fri, 11 Sep 2009 14:55:05 +0000

@HansUS - Notice that both sides of the IF statement reference the same temporary variable, in this case named rtb_in2. I think you are suggesting that it would be more efficient to directly write to the out variable, and you are correct. The reason this model doesn’t do that is because I disabled the expression folding optimization. The model is so simple that with expression folding turned on, both codes were the same. Please see important note 1 above. Thanks for the comment.

By: HansUS

HansUS — Fri, 11 Sep 2009 13:11:13 +0000

I wonder if the pseudo code on the right is correct.
Copy and paste mistake?

Without the Signal storage reuse option set,
the if-branch should use rtb_in1 instead of rtb_in2.

With activated Signal storage reuse option,
both if- and else-branch should directly write to the out variable.

By: Ramin

Ramin — Wed, 12 Aug 2009 18:27:00 +0000

Can this be used to pass in a large structure, then after the first pass, not have the large structure as input?
Like a Data File which gets passed in once, and then not looked passed in after that?

Does this just impact the generated code, or does the Matlab/Simulink Internals fetch the data anyways before the assignments in the code? I’d like to have a selector “first_time_called” then not have the input get copied since it won’t change after the first call in generated code or simulink engine. (Note: values in the file are not known until run time so it can’t be hard coded)

By: Seth

Seth — Tue, 21 Jul 2009 17:22:46 +0000

@Anand Rangaramu - I hope you can turn on this optimization, but I think you should also strive to add explicit specifications of conditional behavior to your model. Stay tuned for a post on that.

By: Anand Rangaramu

Anand Rangaramu — Fri, 12 Jun 2009 16:56:02 +0000

This is great. We need to implement this in our code.