integration tolerance has not met

Hi

I encountered an issue in implementing the growth rate of the tumor. In the following equation, both tumor carrying capacity and tumor volume are species

(d/dt)TumorVolume = r * TumorVolume * log(TumorCarryingCapacity/TumorVolume)

I received a message error that the integration tolerance has not met. I believe it is because tumor carrying capacity and tumor volume are species and they have to be that.

How would I solve this?

Appreciate your help

Answer 1

[Arthur Goldsipe]

If you can share your model or other reproduction steps, then we can likely offer better advice. In the absence of those details, one thing I notice is that the rate equation you provide could easily result in non-finite values. For example, if TumorCarryingCapacity is ever 0, then the log term will be -inf (assuming a positive, finite value for TumorVolume). If r or TumorVolume is also 0 at the same time, then the rate will be NaN.

You could use the SimBiology Model Debugger to step through your simulations to see if non-finite values appear and determine what their source is.