Daniel, Thanks again for getting back to me. Sorry to keep coming back to the same problem. It does seem like there's a problem with the CylindricalGrid1D mesh. I noticed that running the most basic 1D diffusion example with a cylindrical grid doesn't seem to work correctly. With that said, I hope I can impose on you one more time and ask how I should convert a cylindrical coordinate PDE into a rectangular coordinate PDE for FiPy, essentially turning this [image: image.png] into this: [image: image.png]. Previously you said to multiply through by r. Assuming R is the maximum of the variable r, am I looking at this equation [image: image.png] or should I be using this? [image: image.png]If r should still be in the variable format, how would I make that work in FiPy?

Thanks, Dan DeSantis On Thu, Aug 16, 2018 at 6:04 PM Daniel Wheeler <daniel.wheel...@gmail.com> wrote: > Apologies for the slow reply. I hadn't noticed your response until > now. See below. > > On Wed, Aug 8, 2018 at 1:09 PM Daniel DeSantis <desan...@gmail.com> wrote: > > > > Daniel, > > > > Thank you very much for your help.The code does run much better. > > > > I was curious about these lines of code. I'm hoping to understand what > this means so that I can use it if needed, next time. > > > > Thank you again, > > Dan DeSantis > > > > constraint_value = FaceVariable(mesh=mesh) > > T.faceGrad.constrain(constraint_value,mesh.facesLeft) > > > > for sweep in range(sweeps): > > constraint_value[:] = h * ((60. + 273.15) - T.faceValue) > > I only used the above code as it happened to work. It should work > without having to do the update in the loop, but something isn't right > with the way FiPy is updating constraints in the case when the > constraint is not a bare FaceVariable. In other words, we make a face > variable and then say that the constraint depends on that face > variable. We have to explicitly update the face variable in the loop. > > The expression "h * ((60. + 273.15) - T.faceValue" should also be a > face variable and so we should be able to use "T.faceGrad.constrain(h > * ((60. + 273.15) - T.faceValue, mesh.facesLeft)" and not update in > the loop. That doesn't work, however. > > -- > Daniel Wheeler > _______________________________________________ > fipy mailing list > fipy@nist.gov > http://www.ctcms.nist.gov/fipy > [ NIST internal ONLY: https://email.nist.gov/mailman/listinfo/fipy ] > -- Daniel DeSantis

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