Hi, Krishna. This strikes me as a strange way to go about implementing something, so it might be helpful to have a bit more physical details about the system in order to see if the list has proposals for alternative ways to address the problem. The worry about 0's propagating into the rest of the system makes me wonder how you expect the rest of the PDE to interact with the nan's. If values of one PDE are undefined over a particular region, then perhaps the mesh they are defined on should actually end, and boundary conditions should be applied. If only one of the PDE's is undefined over that region, then it would mean having multiple partially overlapping meshes, and that leads to implementation details, but I give this just as an example interpretation of your situation.
Ray On Wed, Jul 13, 2016 at 9:49 AM, Gopalakrishnan, Krishnakumar < krishnaku...@imperial.ac.uk> wrote: > Hello, > > > > I have a regular 2D Cartesian uniformly spaced mesh. > > > > Due to some peculiarities of the physical system that I am currently > working with, the variable of interest in one of my PDEs, (fiPy > CellVariable), is undefined in certain interior node locations, i.e. we > need to constrain them to a value of float(‘nan’), when solving this PDE. > > > > It is not satisfactory to merely constrain them to have a value of 0.0 in > these interior co-ordinates, because a) It is physically inaccurate since > the values are not defined here and b) Because we need to couple this PDE > to other PDEs, the incorrect 0.0 values will propagate to other PDEs, > thereby polluting/corrupting their solutions too. And hence, the full > system of > > > > > > However, the following code snippet was deemed to be illegal when I tried > it out, since FiPy was checking for cellvariables to be strictly numeric > (got a value < eps error) > > > > phi.constrain(float(‘nan’),mesh.y<=1.5) > > > > > > > > How else can we enforce NaNs in these interior nodes in FiPy ? > > > > > > > > Best Regards, > > > > Krishna > > > > > > _______________________________________________ > fipy mailing list > fipy@nist.gov > http://www.ctcms.nist.gov/fipy > [ NIST internal ONLY: https://email.nist.gov/mailman/listinfo/fipy ] > >
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