We have developed an ODE model comprising 25 interrelated equations with common coefficients. This biochemical model, applied in wastewater treatment, is characterized by stiffness. Utilizing the R programming language, we have employed various methods typically used for stiff models, including lsoda, vode, rk4, and others. While the model executes, the results frequently yield negative values, NAN, or only partial values. The equations, coefficients, and initial parameter and variable values are all known, and the time intervals have been carefully checked. Could you please provide insights into what might be causing these issues with our model?
Thank you for providing details about your stiff biochemical ODE model and the challenges you're facing. These types of issues are not uncommon when dealing with complex, stiff systems. Let's explore some potential causes and solutions:
To help diagnose and potentially resolve these issues, I can provide some example R code that implements these suggestions. Would you like to see a template for how to set up and solve a stiff ODE system in R, incorporating some of these recommendations?
Dear Touhidul Alam Seyam,
Thank you very much for the useful information you gave me in the reply. I would be most appreciative if you could kindly share a template for solving a stiff ODE system in R. Your assistance in this matter would be greatly beneficial to my research.
Thank you very much for your time and consideration.
Best regards,
Pourya
Pourya Alipour Atmianlu
I wish best luck to your research and please try the following template that i uploaded. I added some helpful comments too.
Dear Touhidul Alam Seyam,
Many thanks for sharing the code you sent.
Best regards,
Pourya