[petsc-users] nondeterministic behavior with ./program -help | head

Wed Apr 26 16:30:47 CDT 2017

> 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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