How to find the sensitivity of the model output if it is a variable for repeated assignment?

Hi,

I want to find the sensitivity of model output which is a tissue mass for models parameters. I received an red flag that I can't do that for repeaded variable.

How can I handle that?

Thank you.

Answer 1

[Catalytic]

Do what the error message says.

Answer 2

[Arthur Goldsipe]

The solution I generally recommend is to calculate the sensitivities yourself by manualy differentiating the repeated assignment rule and calculating the sensitivity yourself from the local sensitivities that SimBiology can calculate.

For example, if you have a repeated assignment X = A + B, then the sensitivity of X is just the sensitivity of A plus the sensitivity of B. Of course, if A or B are also determined by repeated assignments, you will need to replace those as well. But hopefull this gets the general idea across.

If this suggestion isn't practical, other options include switching to global sensitivity analysis (which doesn't have this restriction on repeated assignments) or implementing your own approximation of local sensitivity analysis (perform multiple simulations and use finite differencing to calculate approximate sensitivities).

[Arthur Goldsipe]

Unfortunately, I can't determine the cause of the error from that message alone. Can you share more detailed reproduction steps, ideally your model and code that reproduces the error?

[Arthur Goldsipe]

I don't see any obvious problem with those steps. Can you copy and paste teh complete error message? Also, what version of MATLAB are you using?

Alternatively, could you share your model directly with MathWorks rather that post it here publicly? If so, please contact me via my profile, and I will give you an email address you can send the files to.

[Day]

This is the complete error message: 'Unable to creat SimFunction'. My Simbiology version is 2024a. I can not share my model publickly. I sent you a message.