Re: [petsc-users] VecView output to HDF5 in 3.12.0 broken ?

Thanks for figuring this out. We should have done this debugging and figured it out. I hunted through the HDF5 docs and includes and though they document the maximum chunk size they do not seem to have any way of getting it using the preprocessor or compiler (that it is not defined by a

Re: [petsc-users] Changing nonzero structure and Jacobian coloring

Because of the difficulty of maintaining a nonzero matrix for such problems aren't these problems often done "matrix-free"? So you provide a routine that computes the action of the operator but doesn't form the operator explicitly (and you hope that you don't need a preconditioner).

[petsc-users] Changing nonzero structure and Jacobian coloring

Hi PETSc users! I have a problem that I am integrating with TS, and I think an implicit method would let me take larger timesteps. The Jacobian is difficult to compute, but, more importantly, the nonzero structure is changing with time, so even if I use coloring and finite differences to compute

Re: [petsc-users] Changing nonzero structure and Jacobian coloring

So you have a fixed "mesh" and fixed number of degrees of freedom for the entire time but the dependency on the function value at each particular point on the neighbor points changes over time? For example, if you are doing upwinding and the direction changes when you used to use values

Re: [petsc-users] Changing nonzero structure and Jacobian coloring

Thanks for the reply, Barry! Unfortunately, this is a particle code (SPH, specifically), so the particle neighbors, which influence the properties, change over time; the degrees of freedom is a constant, as is the particle number. Any thoughts, given the new info? Or should I stick with explicit

Re: [petsc-users] VecView output to HDF5 in 3.12.0 broken ?

Hi PETSc-developers, I think I’ve found the commit that broke this. In MR-1706 , the definition of PETSC_HDF5_INT_MAX was changed from being set to 2147483647 to (~(hsize_t)0). This new

Re: [petsc-users] Makefile problems: environmental variables, includes paths and libraries.

On Tue, 15 Oct 2019, Matthew Agius via petsc-users wrote: > Dear PETSC users, > > This is my first attempt at PETSC package. > > First step, I think I have installed PETSC, well at least no errors. > Now I am trying to run a simple makefile as suggested in the manual > I am confused about

[petsc-users] Makefile problems: environmental variables, includes paths and libraries.

Dear PETSC users, This is my first attempt at PETSC package. First step, I think I have installed PETSC, well at least no errors. Now I am trying to run a simple makefile as suggested in the manual I am confused about undeclared variables in the example makefiles that I am coming across;

Re: [petsc-users] negative grid complexity in GAMG

Mark, It may be caused by some overflow in the calculations somewhere due to your very large sizes and nonzeros but I could not see anything based on a quick inspection of the code. We seem to use double to store the counts which normally would be more than sufficient to hold the

Re: [petsc-users] negative grid complexity in GAMG

I think I now see the bug: the code uses PetscInt lev, nnz0 = -1; which will overflow. It should be using PetscLogDouble for nnz0 You can try changing that one place in the code and see that it now prints a reasonable value for complexity. I will prepare a MR for maint to fix