Moritz,
If you use ARKIMEX(3,4,5) and force the time step to be small [try
setting -ts_dt_max] - do you still get negatives? If you are not, it may
be due to the time steps being too large relative to the dynamics of
your system, forcing it in the negative territory. This is typical when
one d
Indeed, various time steppers can take advantage of the differential
form provided and also can serve as a sanity check (e.g., warn users
before they use an explicit solver on an index-2 DAE). To my knowledge,
we do not have solvers that take advantage of semi-explicit DAEs, but
it's good pract
I believe this is intended to work with most any implicit solver,
*provided* the initial conditions are compatible. It was added by Emil,
but I don't see it explicitly tested in PETSc.
"Huck, Moritz via petsc-users" writes:
> Hi,
> TS_EQ_DAE_SEMI_EXPLICIT_INDEX(?) are defined in TSEquationType
You could try the master branch of PETSc that uses a much more recent branch
of hdf5
When you did the --download-hdf5 did you also do --download-zlib and
--download-szlib (though I would hope hdf5 would give you a very useful error
message that they need to be installed instead of the va
Dear All,
Not sure if this is the right place to ask hdf5 question. I installed
hdf5 through PETSc configuration --download-hdf5=yes. The code runs
without problem except the function to create compressed data (red part
shown below).
!c create local memory space and hyperslab
call h5
Steve,
There are two levels at which "out of domain" (infeasible) errors
can/should be indicated:
1) First call TSSetFunctionDomainError(). TS calls your provided function
when candidate solutions are generated, if the new solution is not feasible, as
indicated by this function,
Hello,
I have another beginner's PETSc question. Apologies if the solution is
obvious, but I've looked around the manual and the API and haven't yet
spotted a solution.
I'm solving a nonlinear problem using the BDF TSP (although the same
issue arises if I use BEULER and other TS - it's not
Hi,
TS_EQ_DAE_SEMI_EXPLICIT_INDEX(?) are defined in TSEquationType but not
mentioned in the manual.
Is this feature functional ?
If yes how do I have to define the RHSFunction?
(I am asking since the ODE variant has it defined as G= M^-1 g, which cannot
work for a DAE)
Best Regards,
Moritz
