cantera | Chemical kinetics , thermodynamics , and transport tool suite | Dataset library

I am trying to get a solution for a stiff ODE problem where at each integration step, i have to modify the solution vector before continuing on the integration. For that, i am using scipy.integrate.ode, with the integrator VODE, in bdf mode. Here is a simplified version of the code i am using. The function is much more complex than that and involve the use of CANTERA.

I have a python code (example from Cantera.org) that uses scipy.integrate.ode to solve a system of ODE. The code works fine and the results are reasnoable. However, I noticed something about the ode solver that does not make sense to me.

I have a put a print function inside (print("t inside ODE function", t)) the function the calculates the derivative vector (__call__(self, t, y)), and outside that function in the while loop (print("t outside ODE function", solver.t);). I expect that inside print has to be called when the solver does the time integration, and then the outside print is called. In other words, two "t outside ODE function" cannot appear right after another without "t inside ODE function" in between. However, this occurs in some of iterations in the while loop, which mean the solver does the integration without calculating the derivatives.

I am wondering how this is possible

I want to perform multiple ARIMA and VECM at the same time.

Specifically, I want a time series for every "Sector", which goes from 2007Q1 to 2018Q4.

I tried to do it with a for loop but it is not working properly.

Is there a specific function to create this kind of result?

Data

I have a dictionary of bigrams, which was created as