MATLAB Answers


Reg. PDEPE 's internal discretization of time

Asked by Harry
on 4 May 2014
Latest activity Commented on by assionvi hove kouevi on 12 May 2017
Hello, I am solving a reaction diffusion equation where there is a radiation term. Now the radiation is given once per day let's say instantaneously. But instead of modelling this instantaneous radiation I took time step to be one day. And modelling the radiation only as a function of space(or x). So I would expect this radiation term to be counted only once and would be equivalent to instantaneous radiation. But I came to know from someone that while solving the problem pdepe might be discretizing time in it's own way during the simulation. Is this so? If this is so then I am in trouble since the radiation term would no longer be counted only once and I would end up giving an overdose. Can someone please shed some light on how pdepe discretizes time internally over and above the discretization I specify? Thanks


Sign in to comment.



1 Answer

Answer by Bill Greene on 4 May 2014
 Accepted Answer

pdepe uses the variable time step ODE solver, ode15s, internally.
The time step size is automatically chosen by ode15s to obtain a prescribed accuracy.
The time discretization that you specify to the pdepe function is only to tell ode15s the points in time where you would like output.

  1 Comment

Hi Bill,
Is there a way to extract the PDEPE 's internal discretization of time for a given maximum time step?

Sign in to comment.