[dli]

Hi guys,
I am writing a code to simulate the detonation ,but I don't have any efficient method to treat those stiff source terms. The subcycle in the global timestep was used ,but it's only 1-order,it's not very accurate in the unsteady flow.I also read some papers about the linearly point implicit method which avoid the stiff source problem,but it's very difficult to derive the source Jacobi matrix,and it's different from the mechanisms, so I want to get the Jacobi matrix by the standard different quotients,is it appropriate to get Jacobi matrix from this method?(may it is a little time-consuming to do this,but i think it's general for many mechanisms)

so ,any one can give me help or give me some suggestions about this?