On Wed, 28 Apr 2010, liang cheng wrote:
Stack frames: 10
0: print_trace(std::ostream&)
1: QBase::n_points() const
2: assemble_ldm(EquationSystems&, std::string const&)
This is the content in the traceout_0_?????.txt, the ????? varies according to
different case. I am not good at debugging, the falling one seems the No.10,
which is the name of executable file '/dld3d_v5-dbg() [0x441d69] '. Does that
mean
the whole program collapsed because of something wrong in the code?
No, the failure was the n_points() call in assemble_ldm(). The
quadrature rule in that function isn't getting initialized properly.
/usr/include/c++/4.4/debug/vector:272:error: attempt to subscript container
with out-of-bounds index 0, but container only holds 0 elements.
Objects involved in the operation:
sequence "this" @ 0x0x7fffd1904378 {
type = NSt7__debug6vectorIdSaIdEEE;
}
No traceout_0_xxx files generated this time, I guess the error comes from the
vector definition, I will check the whole vectors later.
This is a libstdc++ generated error; to get a stack trace there the
best way is to run from within gdb and type "where" after it crashes.
The model is about the solid elasticity problem, which is a second order
time dependent PDEs, so probably the ex8 is a good example for me.
Yes, I think so.
maybe I should get the steady case work before jumping to the transient problem.
Probably a good idea.
> Yes. With one variable on a grid of a million trilinear hexahedra,
> for instance, the SparseMatrix will be a (roughly) 1000000x1000000
> matrix (which fits into memory because we only store the 1000000x27
> potentially non-zero entries) while the DenseMatrix will be a 8x8
> matrix with all 64 entries typically non-zero.
Sounds the Densematrix is quit efficient,
Yes, for one element. A dense matrix for the whole problem would have
1000000x1000000 entries and would require around 8,000GB of memory.
I am thinking how difficult to develop another 2nd time rate solver
such as HHT. is it possible to get new time solver done with one
source file and header file?
Yes, but difficult. I wouldn't attempt it yet. Using ex8 as a
template for your own application isn't exactly easy, but it's a lot
easier than using newmark_system.* as a template for your own
integrator would be.
---
Roy
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