I don't think you want to hash floating point values, but I've had a number of
reasons to want spatial hashing for near-neighbor queries in PETSc and that
would be a great contribution. (Spatial hashes have a length scale and compute
integer bins.)
Brandon Denton via petsc-users <petsc-users@mcs.anl.gov> writes:
> Good Afternoon,
>
> Is there a structure within PETSc that allows storage of a value using a
> triple similar to PetscHMapIJSet with the key using a struct{PetscScalar i,
> j, k;}?
>
> I'm trying to access mesh information (the shape function coefficients I will
> calculate prior to their use) who's values I want to store in the auxiliary
> array available in the Residual Functions of PETSc's FEM infrastructure.
> After some trial and error work, I've come to the realization that the
> coordinates (x[]) available in the auxiliary functions is the centroid of the
> cell/element currently being evaluated. This triplet is unique for each
> cell/element for a valid mesh so I think it's reasonable to use this triplet
> as a key for looking up stored values unique to each cell/element. My plan is
> to attached the map to the Application Context, also available to Auxiliary
> Functions, to enable these calculations.
>
> Does such a map infrastructure exist within PETSc? If so, could you point me
> to a reference for it? If not, does anyone have any suggestions on how to
> solve this problem?
>
> Thank you in advance for your time.
> Brandon Denton
