Rework rate calculation
Currently
compute_rate_coef() subroutine is called once for each cell. The routine loops over reactions and the time dependence of physical conditions taken into account by substituting the arrays of physical conditions into the expressions for the rate coefficients.
It is difficult to switch between reaction temperature ranges as the temperature changes between time steps.
Plan
compute_rate_coef() should compute the rates only for a single cell and single time step. This would allow the better treatment of temperature validity ranges and would make it possible to compute reaction rate coefficients at the exact time when the solver requests them.
A wrapper should be written around compute_rate_coef() to replace the current functionality and pseudo-time dependent models should call the routine only once.