How can I modify the default options (like RelTol' and 'AbsTol') of the pde solver when using the PDE toolbox?

When working in 1D, I can modify the default options of the solver by using odeset and then calling the 'options' with pdepe, for example:

options = odeset('RelTol',1e-13,'AbsTol',1e-13);

sol = pdepe(m,'pde','ic','bc',x,t,options)

Now I am working in a 2D probelm and I am using the PDE toolbox. How can I especify options when working with the PDE toolbox? I use the command line function solvepde and I I would like to set more strict Relative error tolerance and Absolute error tolerance.

Apparently, the function solvepde calls ode15s which allows the especification of 'options'.

Thank you.

Answer 1

[Ravi Kumar]

You can edit those tolerances directly using the model object properties. Say,

model = createpde(...

User model the set RelTol as:

model.SolverOptions.RelativeTolerance = 1E-6

Regards,

Ravi

[Mario Di Salvo]

Thank you, Ravi, that is exactly what I was looking for and worked perfectly!

[Mario Di Salvo]

Hi Ravi,

I wonder if there is an equivalent of the option "NonNegative" in pdepe that can be used with the PDE toolbox. I want to force my solutions to be non-negative.

Thank you.

[Ravi Kumar]

There is no option to force NonNegative constraint. Solution is definied by the PDE coefficients BCs, and ICs, if solution exists.

Regards,

Ravi

[Hitesh Saini]

Can Someone please elaborate the meathod?

i am not getting what is this.

model = createpde(...

this is for model Right?

i mean how can i change the relTol if i am using the equations to get results.

[Ravi Kumar]

Post details of your question and what you have tried so far. Quickly: You can set up a model, define the equaion using various coefficients, while soliving you can also assign value of tolerances to be used. Check help and documenation on PDEModel. I would also suggest creating a new post if your question in not related to the one posted here.

Regards,

Ravi