[petsc-users] nondeterministic behavior with ./program -help | head
Barry Smith
bsmith at mcs.anl.gov
Wed Apr 26 18:32:34 CDT 2017
> On Apr 26, 2017, at 5:44 PM, Jed Brown <jed at jedbrown.org> wrote:
>
> PETSc is the only package I know for which "./app -help" does everything
> that "./app" would do, with extra output. It is an unfortunate
> consequence of extensibility that we can't exit immediately. What if we
> had a function the user could call to exit early and cleanly after all
> options have been processed? Maybe something like:
>
> PetscInitialize
> ...
> if (PetscHelpActive()) {
> TSSetDuration(ts,1,PETSC_DEFAULT);
> PetscExitSilently();
> }
>
> where PetscExitSilently doesn't print -malloc or -log_view or the like.
Yuck!
>
> We should probably also have "-help snes,ksp_fieldsplit" that would only
> print help for options with those prefixes.
This would be useful.
>
> Barry Smith <bsmith at mcs.anl.gov> writes:
>
>> Ed
>>
>> I think want you want is something like
>>
>> ./program -intro
>>
>> that causes the help message to PetscInitialize() to be printed and then have the program end.
>>
>> We can add this, -intro is not a great name, any idea for a better name?
>>
>> Barry
>>
>>> On Apr 26, 2017, at 4:30 PM, Ed Bueler <elbueler at alaska.edu> wrote:
>>>
>>>> Is ./ex5 -help -no_signal_handler | head good enough?
>>>
>>> Umm. It eliminates the nondeterminism. Should discovery of options for petsc user applications go via error messages? (Or asking users to remember "-no_signal_handler" to avoid?) I don't understand signal handling well-enough to recommend a better way ... maybe there is no better way for |head.
>>>
>>> The best alternative I can think of is if my codes supply the program name for the "const char man[]" argument of PetscOptionsXXX(). Then I can suggest this to users:
>>>
>>> ./program -help |grep program
>>>
>>> Is this a mis-use of the "man" argument?
>>>
>>> Ed
>>>
>>> PS Amused to find "This routine should not be used from within a signal handler." in the man page for MPI_Abort(), which I reached by clicking on the call to MPI_Abort() in the view of PetscSignalHandlerDefault(). ;-)
>>>
>>>
>>> On Wed, Apr 26, 2017 at 12:55 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>>>
>>> Is
>>>
>>> ./ex5 -help -no_signal_handler | head
>>>
>>> good enough?
>>>
>>> Normally we won't want to turn off catching of PIPE errors since it might hide other errors.
>>>
>>> Barry
>>>
>>>
>>>
>>>> On Apr 26, 2017, at 3:31 PM, Ed Bueler <elbueler at alaska.edu> wrote:
>>>>
>>>> Dear Petsc --
>>>>
>>>> Copied at the bottom is the behavior I get for ex5.c in snes examples/tutorials. When I do
>>>>
>>>> $./ex5 -help |head
>>>>
>>>> I get a "Caught signal number 13 Broken Pipe" or just a version string. Randomly, one or the other.
>>>>
>>>> I know this has come up on petsc-users before:
>>>> http://lists.mcs.anl.gov/pipermail/petsc-users/2014-May/021848.html
>>>> The claim was that the SIGPIPE error is standard behavior.
>>>>
>>>> My real issue (feature request?) is that when writing a petsc application I want a rational help system. Suppose "program.c" has options with prefix "prg_". The user doesn't know the prefix yet (I could have used "prog_" as the prefix ...) The petsc-canonical help system is (I believe)
>>>>
>>>> ./program -help |grep prg_
>>>>
>>>> for program.c-specific options. Works great if you know to look for "prg_". My plan for my applications is to put the prefix in the first line or two of my help string, the user can discover the prefix by
>>>>
>>>> ./program -help |head
>>>>
>>>> and then use "-help |grep -prg_" and etc.
>>>>
>>>> So my question is: Can petsc be set up to not generate an error message when the help system is used in a correct way? (I.e. catching return codes when writing, or handling SIGPIPE differently?) Or, on the other hand, can someone suggest a better help system that irritates less?
>>>>
>>>> Thanks!
>>>>
>>>> Ed
>>>>
>>>> ~/petsc/src/snes/examples/tutorials[master*]$ ./ex5 -help |head
>>>> Bratu nonlinear PDE in 2d.
>>>> We solve the Bratu (SFI - solid fuel ignition) problem in a 2D rectangular
>>>> domain, using distributed arrays (DMDAs) to partition the parallel grid.
>>>> The command line options include:
>>>> -par <parameter>, where <parameter> indicates the problem's nonlinearity
>>>> problem SFI: <parameter> = Bratu parameter (0 <= par <= 6.81)
>>>>
>>>> -m_par/n_par <parameter>, where <parameter> indicates an integer
>>>> that MMS3 will be evaluated with 2^m_par, 2^n_par--------------------------------------------------------------------------
>>>> Petsc Development GIT revision: v3.7.6-3453-ge45481d470 GIT Date: 2017-04-26 13:00:15 -0500
>>>> [0]PETSC ERROR: ------------------------------------------------------------------------
>>>> [0]PETSC ERROR: Caught signal number 13 Broken Pipe: Likely while reading or writing to a socket
>>>> [0]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger
>>>> [0]PETSC ERROR: or see http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind
>>>> [0]PETSC ERROR: or try http://valgrind.org on GNU/linux and Apple Mac OS X to find memory corruption errors
>>>> [0]PETSC ERROR: likely location of problem given in stack below
>>>> [0]PETSC ERROR: --------------------- Stack Frames ------------------------------------
>>>> [0]PETSC ERROR: Note: The EXACT line numbers in the stack are not available,
>>>> [0]PETSC ERROR: INSTEAD the line number of the start of the function
>>>> [0]PETSC ERROR: is given.
>>>> [0]PETSC ERROR: [0] PetscVFPrintfDefault line 240 /home/ed/petsc/src/sys/fileio/mprint.c
>>>> [0]PETSC ERROR: [0] PetscHelpPrintfDefault line 622 /home/ed/petsc/src/sys/fileio/mprint.c
>>>> [0]PETSC ERROR: [0] PetscOptionsBegin_Private line 29 /home/ed/petsc/src/sys/objects/aoptions.c
>>>> [0]PETSC ERROR: [0] PetscObjectOptionsBegin_Private line 61 /home/ed/petsc/src/sys/objects/aoptions.c
>>>> [0]PETSC ERROR: [0] PetscDSSetFromOptions line 218 /home/ed/petsc/src/dm/dt/interface/dtds.c
>>>> [0]PETSC ERROR: [0] DMSetFromOptions line 747 /home/ed/petsc/src/dm/interface/dm.c
>>>> [0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
>>>> [0]PETSC ERROR: Signal received
>>>> [0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting.
>>>> [0]PETSC ERROR: Petsc Development GIT revision: v3.7.6-3453-ge45481d470 GIT Date: 2017-04-26 13:00:15 -0500
>>>> [0]PETSC ERROR: ./ex5 on a linux-c-dbg named bueler-leopard by ed Wed Apr 26 11:22:07 2017
>>>> [0]PETSC ERROR: Configure options --download-mpich --with-debugging=1
>>>> [0]PETSC ERROR: #1 User provided function() line 0 in unknown file
>>>> application called MPI_Abort(MPI_COMM_WORLD, 59) - process 0
>>>> [unset]: aborting job:
>>>> application called MPI_Abort(MPI_COMM_WORLD, 59) - process 0
>>>> ~/petsc/src/snes/examples/tutorials[master*]$ ./ex5 -help |head
>>>> Bratu nonlinear PDE in 2d.
>>>> We solve the Bratu (SFI - solid fuel ignition) problem in a 2D rectangular
>>>> domain, using distributed arrays (DMDAs) to partition the parallel grid.
>>>> The command line options include:
>>>> -par <parameter>, where <parameter> indicates the problem's nonlinearity
>>>> problem SFI: <parameter> = Bratu parameter (0 <= par <= 6.81)
>>>>
>>>> -m_par/n_par <parameter>, where <parameter> indicates an integer
>>>> that MMS3 will be evaluated with 2^m_par, 2^n_par--------------------------------------------------------------------------
>>>> Petsc Development GIT revision: v3.7.6-3453-ge45481d470 GIT Date: 2017-04-26 13:00:15 -0500
>>>> ~/petsc/src/snes/examples/tutorials[master*]$
>>>>
>>>>
>>>> --
>>>> Ed Bueler
>>>> Dept of Math and Stat and Geophysical Institute
>>>> University of Alaska Fairbanks
>>>> Fairbanks, AK 99775-6660
>>>> 301C Chapman
>>>
>>>
>>>
>>>
>>> --
>>> Ed Bueler
>>> Dept of Math and Stat and Geophysical Institute
>>> University of Alaska Fairbanks
>>> Fairbanks, AK 99775-6660
>>> 301C Chapman
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