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

Barry Smith bsmith at mcs.anl.gov
Wed Apr 26 18:33:52 CDT 2017 

   Does -help_only make sense? Not to me, I would think this would mean print all the help but don't run anything; but this is impossible since it has to run in order to know what help to print.


> On Apr 26, 2017, at 5:34 PM, Ed Bueler <elbueler at alaska.edu> wrote:
> 
> [Missed reply all.]
> 
> ---------- Forwarded message ----------
> From: Ed Bueler <elbueler at alaska.edu>
> Date: Wed, Apr 26, 2017 at 2:33 PM
> Subject: Re: [petsc-users] nondeterministic behavior with ./program -help | head
> To: Barry Smith <bsmith at mcs.anl.gov>
> 
> 
> Yes, I thought of something vaguely like that.  How about
> 
> ./program -help_string
> 
> or -help_only?
> 
> Ed
> 
> On Wed, Apr 26, 2017 at 2:28 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
> 
>   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
> 
> 
> 
> 
> -- 
> 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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