[Paraview] ParaView thinks that it does not have a wind blade reader

[David E DeMarle]

Two issues need to be fixed.
1) that behavior in 3.14 is there because of this fix which we had to
rush in just before the 3.14 release.

Committer: Utkarsh Ayachit <utkarsh.ayachit at kitware.com>  2012-02-08 17:12:18
Parent: e401d569f6e54c49c3497852463f6b13a01da8b6 (Update version after
3.14.0-RC1 tag.)
Child:  99fdb1aeb5997c29b43393f45a478c4b53a23109 (Merge topic
'fix_windblade_segfault')
Branches: many (31)
Follows: v3.14.0-RC1
Precedes: v3.14.0-RC2

    Fix segfault with ParaView built with MPI when opening *.vtr files.

    The problem was that vtkWindBlade reader was getting created to test
    "CanReadFile" and that would cause segfault unless MPI was initialized.

    Solved the problem by added support to vtkSMReaderFactory to respect the
    ProcessSupport flag on SourceProxy and change windblade reader XML
to say that
    it only works in parallel.

In other words, Windblade reader's Constructor should not take it upon
itself to initialize MPI.

Once that is fixed, we get to issue 2 before paraview 4.0

2) VTK's new modularization has the rule that no module can behave
differently with parallel (or most other cmake config options) turned
configured on or off. This is so because it makes it very hard to
package VTK when the libs behave differently in different situations.

Ie, we can't have any more
#ifdef VTK_USE_MPI
do something
#else
do something different
#endif
in VTK classes.

Now if we want a class to behave differently when MPI is turned on or
off we have to make a serial only version in a non MPI dependent
module and a subclass of that in an MPI dependent module.

David E DeMarle
Kitware, Inc.
R&D Engineer
21 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-881-4909


On Thu, Jul 19, 2012 at 3:52 PM, Sohail Shafii <sohailshafii at yahoo.com> wrote:
> When running serially, vtkSMReaderFactory::CanReadFile sees that the session
> has a single process.  As such, on line 660 it realizes that the source
> proxy's process support (in this case the source is a vtkWindBladeReader
> proxy) is multiple processes, which causes a return of "false" from that
> function.  This makes ParaView think that the wind blade reader can't read a
> .wind file in serial.  According to Andy, the reader works find in parallel.
>
> I assume that a fix for this is pretty trivial? It never did this before in
> previous versions of ParaView and I think that the wind blade reader code
> has remained mostly the same. Andy mentioned some details in person when he
> was talking with Jon but at that time I didn't know as much as I do now.
> There is a mention below about enabling the filter in serial and parallel --
> is this done in a xml file?
>
> Sohail
>
> ________________________________
> From: David E DeMarle <dave.demarle at kitware.com>
> To: Sohail Shafii <sohailshafii at yahoo.com>
> Cc: Andy Bauer <andy.bauer at kitware.com>; "migichen at gmail.com"
> <migichen at gmail.com>; "paraview at paraview.org" <paraview at paraview.org>;
> "Woodring, Jonathan L" <woodring at lanl.gov>
> Sent: Tuesday, July 17, 2012 7:00 PM
>
> Subject: Re: [Paraview] ParaView thinks that it does not have a wind blade
> reader
>
> Each file that has an association with that file extension, made via the
> XML, has its CanReadFile method called. Put a breakpoint there to determine
> if ParaView even knows about that reader.
>
> On Tuesday, July 17, 2012, Sohail Shafii wrote:
>
> Sorry, but I meant to ask a different question.  Here's what Andy said
> before, which relates to my concern:
> ">
>> I went through the code and it jogged my memory about previous problems
>> with
>> it. It had an explicit MPI call in the constructor that would cause
>> problems
>> when paraview wasn't getting built with MPI. Any time a user tried to open
>> an unknown file it would try to create a windblade reader to see if the
>> reader could handle the file and this would cause a crash. If you launch a
>> separate pvserver the wind blade reader will be available in the gui."
>
> What I meant was; which ParaView class "creates" or "tests" a reader to see
> if it can handle a file? The test code you specified has a predefined data
> set that is loaded in, and I think is more of an example to your average
> user. Correct me if I'm wrong.
>
> So basically ParaView will recognize the file extension, tries to load it,
> crashes somewhere, then asks you specify the data format from a dialog.  I'm
> trying to figure out where it crashes so that I can see how that relates to
> the wind blade reader class and any MPI calls that are in there.
>
> Sohail
>
> Subject: Re: [Paraview] ParaView thinks that it does not have a wind blade
> reader
>
> kargad:ParaView demarle$ find . -name "*WindBlade*" -print
> ---> ./VTK/IO/Parallel/Testing/Cxx/TestWindBladeReader.cxx
> ./VTK/IO/Parallel/vtkWindBladeReader.cxx
> ./VTK/IO/Parallel/vtkWindBladeReader.h
>
> David E DeMarle
> Kitware, Inc.
> R&D Engineer
> 21 Corporate Drive
> Clifton Park, NY 12065-8662
> Phone: 518-881-4909
>
>
> On Tue, Jul 17, 2012 at 2:09 PM, Sohail Shafii <sohailshafii at yahoo.com>
> wrote:
>> What is the class that is responsible for testing to reader to see if it
>> can
>> open the .wind file?
>>
>> Sohail
>>
>> ________________________________
>> From: Andy Bauer <andy.bauer at kitware.com>
>> To: Sohail Shafii <sohailshafii at yahoo.com>
>> Cc: "Woodring, Jonathan L" <woodring at lanl.gov>; Sebastien Jourdain
>> <sebastien.jourdain at kitware.com>; "migichen at gmail.com"
>> <migichen at gmail.com>;
>> "paraview at paraview.org" <paraview at paraview.org>
>> Sent: Wednesday, July 11, 2012 10:53 AM
>>
>> Subject: Re: [Paraview] ParaView thinks that it does not have a wind blade
>> reader
>>
>> I was reluctant to enable the reader in serial (i.e. not using MPI IO
>> which
>> I think is getting done by default with the parallel build) because of the
>> following warnings that I got:
>>
>> Warning: In /home/acbauer/CODE/ParaView/
>> ParaView/VTK/IO/Parallel/vtkWindBladeReader.cxx, line 942
>> vtkWindBladeReader (0x3a0c800): WindBladeReader error reading file:
>> /home/acbauer/DATA/VTKLargeData/Data/WindBladeReader/test1_topo.wind
>> Premature EOF while reading block of data. Expected 896000 but got 0
>>
>> I just assumed that it was getting bad results so I didn't check the
>> serial
>> output with the parallel output. In either case the code should be changed
>> before enabling it in serial so that it reads the files correctly and
>> doesn't produce any warning messages.
>>
>> Andy
>>
>> On Wed, Jul 11, 2012 at 12:04 PM, Sohail Shafii <sohailshafii at yahoo.com>
>> wrote:
>>
>> I'm not aware of any option to build/link against mpi-io.  This is just a
>> standard build with mpi support that suffers from this issue.
>>
>> The ParaView website's builds also have the same bug.
>>
>> ________________________________
>> From: "Woodring, Jonathan L" <woodring at lanl.gov>
>> To: Sohail Shafii <sohailshafii at yahoo.com>; Andy Bauer
>> <andy.bauer at kitware.com>; Sebastien Jourdain
>> <sebastien.jourdain at kitware.com>
>> Cc: "migichen at gmail.com" <migichen at gmail.com>; "paraview at paraview.org"
>> <paraview at paraview.org>
>> Sent: Tuesday, July 10, 2012 10:06 AM
>>
>> Subject: Re: [Paraview] ParaView thinks that it does not have a wind blade
>> reader
>>
>> I added the MPI calls to be in sync with what was being added in the
>> simulation.
>>
>> In the SuperComputing demo last year, we updated both the HiGrad FireTec
>> to
>> use MPI-IO and likewise ParaView to do the same thing.
>>
>> It w
>
>
>
> --
> David E DeMarle
> Kitware, Inc.
> R&D Engineer
> 21 Corporate Drive
> Clifton Park, NY 12065-8662
> Phone: 518-881-4909
>
>