[petsc-users] nondeterministic behavior with ./program -help | head
Jed Brown
jed at jedbrown.org
Wed Apr 26 17:44:24 CDT 2017
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.
We should probably also have "-help snes,ksp_fieldsplit" that would only
print help for options with those prefixes.
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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