Trouble inspecting Teuchos::SerialDenseMatrix in gdb

[jeff788]

@trilinos/teuchos
@bartlettroscoe

Is there a good way to inspect a Teuchos::SerialDenseMatrix in gdb? I'm having an issue with an LU factorization with LAPACK on a 6x6 SerialDenseMatrix "A", and I'm trying to diagnose the problem by inspecting the input matrix. When I try to inspect any elements of the matrix this is what happens:

(gdb) p A
$30 = {Teuchos::CompObject = {
vptr.CompObject = 0x7ffff756e708 <vtable for Teuchos::SerialDenseMatrix<int, double>+16>,
flopCounter = 0x0}, Teuchos::Object = {
vptr.Object = 0x7ffff756e730 <vtable for Teuchos::SerialDenseMatrix<int, double>+56>,
static tracebackMode = -1, label = ""}, <Teuchos::BLAS<int, double>> = {
vptr.BLAS = 0x7ffff756e770 <vtable for Teuchos::SerialDenseMatrix<int, double>+120>},
numRows = 6, numCols_ = 6, stride_ = 6, valuesCopied_ = true, values_ = 0x81fa9d70}
(gdb) p A(0,0)
Invalid data type for function to be called.
(gdb) p A.values()
./mesh_transfer.sh: line 2: 1692 Segmentation fault gdb /home/burg137/Projects/FY2018/NRAP/E4D/e4d_tools/MeshTransfer/bin/dream2tetgen

I also get a Segmentation fault if I try to print out the size of an ArrayRCP with ArrayRCP::size(), while I can inspect individual elements in the ArrayRCP with the [] accessor.

Thanks,

Jeff

[bartlettroscoe]

@jeff788,

My personal experience with GDB is that I have not been able to use 'print any_cxx_func()` for an C++ function for many years (perhaps ever). All that I have been able to to do is print raw data. So to get the size, you will need to print the difference of the two pointers into a Teuchos::RCP, for example. Does you GDB allow you to print any C++ function?

My advice is to use a debugger that works, like TotalView or just use trusty 'std::ostream' statements in C++ code. Or just get used to debugging raw code and printing raw data. But for debugging matrices, I would just print them out in C++ and avoid the debugger until I had to use it for some reason.

Have other Teuchos or Trilinos developers had a different experience with GDB than what I described above?

[DrBooom]

Use DDT or if you like debuggers that crash, TotalView. Chasing pointers is much easier in TotalView, so the crash rate may be tolerable. Chris Luchini

…

________________________________ From: Roscoe A. Bartlett <[email protected]> Sent: Wednesday, October 4, 2017 17:49 To: trilinos/Trilinos Cc: Subscribed Subject: [EXTERNAL] Re: [trilinos/Trilinos] Trouble inspecting Teuchos::SerialDenseMatrix in gdb (#1817) @jeff788<https://github.com/jeff788>, My personal experience with GDB is that I have not been able to use 'print any_cxx_func()` for an C++ function for many years (perhaps ever). All that I have been able to to do is print raw data. So to get the size, you will need to print the difference of the two pointers into a Teuchos::RCP, for example. Does you GDB allow you to print any C++ function? My advice is to use a debugger that works, like TotalView or just use trusty 'std::ostream' statements in C++ code. Or just get used to debugging raw code and printing raw data. But for debugging matrices, I would just print them out in C++ and avoid the debugger until I had to use it for some reason. Have other Teuchos or Trilinos developers had a different experience with GDB than what I described above? - You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub<#1817 (comment)>, or mute the thread<https://github.com/notifications/unsubscribe-auth/AI6-Wn_KEpKsk3Ly4iGRGKdqeeQieKKJks5spBmAgaJpZM4PuTRK>.

[jeff788]

I usually use gdb for pretty simple things, and have for a long time, so I guess I didn't realize how far behind these other debuggers it is. I guess I'll get myself on the learning curve. Thanks for the quick responses!

[bartlettroscoe]

@jeff788, okay to close this GitHub Issue?

[jeff788]

Yes, thanks for your time.