[Paraview] Temporal shift with Python Programmable Filter
Moreland, Kenneth
kmorel at sandia.gov
Tue Feb 5 14:35:59 EST 2008
If you look in the code for vtkTemporalShiftScale, you will see that there is a place in request data where it shifts the time values for the root temporal data set object (starting at about line 110). The patch I gave you should change the Shift 1 UnstructuredGrid to t = 4.0.
-Ken
> -----Original Message-----
> From: paraview-bounces+kmorel=sandia.gov at paraview.org [mailto:paraview-
> bounces+kmorel=sandia.gov at paraview.org] On Behalf Of Eric Monson
> Sent: Tuesday, February 05, 2008 12:00 PM
> To: ParaView List
> Subject: Re: [Paraview] Temporal shift with Python Programmable Filter
>
> I'll try the patch later this afternoon when I have more time and see
> if that helps.
>
> With your tip I was able to probe the DATA_TIME_STEPS for all the data
> sets, and the result seems a little strange to me -- see if this helps:
>
> e.g.
> Shift 0 TemporalDataSet: t = 4.0
> Shift 0 UnstructuredGrid: t = 4.0
> Shift 1 TemporalDataSet: t = 4.0 <---
> Shift 1 UnstructuredGrid: t = 3.0
> Output UnstructuredGrid (copy of shift 1 UG): t = 3.0
>
> Should that Shift 1 TemporalDataSet really have t = 4.0 -- shouldn't
> it be t = 3.0 in that case?
>
> Thanks,
> -Eric
>
>
> On Feb 5, 2008, at 1:09 PM, Moreland, Kenneth wrote:
>
> > The data object's time is stored in an information object maintained
> > by the data object with the key vtkDataObject::DATA_TIME_STEPS().
> > In C++, you can get this with something like
> >
> > data->GetInformation()->Get(vtkDataObject::DATA_TIME_STEPS()).
> >
> > You might try applying the following patch to
> > vtkTemporalShiftScale.cxx. It adjusts the time stamp on the
> > internal data objects so that they match the time requested. I
> > never checked this in because I do not know if it will adversely
> > affect anything else. If it fixes your problem, we should consider
> > it.
> >
> > -Ken
> >
> >
> > kmorel1 1> cvs diff -u vtkTemporalShiftScale.cxx
> > Index: vtkTemporalShiftScale.cxx
> > ===================================================================
> > RCS file: /cvsroot/ParaView3/ParaView3/VTK/Hybrid/
> > vtkTemporalShiftScale.cxx,v
> > retrieving revision 1.4
> > diff -u -r1.4 vtkTemporalShiftScale.cxx
> > --- vtkTemporalShiftScale.cxx 7 Sep 2006 18:01:31 -0000 1.4
> > +++ vtkTemporalShiftScale.cxx 5 Feb 2008 18:07:06 -0000
> > @@ -121,7 +121,18 @@
> > outData->GetInformation()->Set(vtkDataObject::DATA_TIME_STEPS(),
> > outTimes, inLength);
> > delete [] outTimes;
> > -
> > +
> > + // adjust the time steps of the internal data
> > + for (i = 0; i < (int)outData->GetNumberOfTimeSteps(); i++)
> > + {
> > + vtkInformation *dataInfo = outData->GetDataSet(i, 0)-
> > >GetInformation();
> > + int numtimes = dataInfo-
> > >Length(vtkDataObject::DATA_TIME_STEPS());
> > + double *times = dataInfo->Get(vtkDataObject::DATA_TIME_STEPS());
> > + for (int j = 0; j < numtimes; j++)
> > + {
> > + times[j] = times[j]*this->Scale + this->Shift;
> > + }
> > + }
> > return 1;
> > }
> >
> >
> >> -----Original Message-----
> >> From: Eric Monson [mailto:emonson at cs.duke.edu]
> >> Sent: Tuesday, February 05, 2008 10:39 AM
> >> To: Moreland, Kenneth
> >> Cc: ParaView List
> >> Subject: Re: [Paraview] Temporal shift with Python Programmable
> >> Filter
> >>
> >> Hey Ken,
> >>
> >> That sounds like a reasonable guess. If that's the problem, do you
> >> know if there's a way to force the update to the correct time? I also
> >> can't seem to find any way of getting at the data object's time
> >> value...
> >>
> >> It's just tough for me to figure out how to debug this one, unless
> >> someone can see something I've obviously left out.
> >>
> >> Thanks,
> >> -Eric
> >>
> >>
> >> On Feb 5, 2008, at 12:03 PM, Moreland, Kenneth wrote:
> >>
> >>> This is a total guess, but maybe it has something to do with the
> >>> time value placed in the data set. Data objects often hold the time
> >>> value on which they are supposed to be defined. Maybe when you copy
> >>> the shifted data, its time value is also shifted. When you then
> >>> step the time, the new time now matches the shifted time from the
> >>> last time update. Perhaps the pipeline sees the time match and does
> >>> not update the pipeline.
> >>>
> >>> -Ken
> >>>
> >>>> -----Original Message-----
> >>>> From: paraview-bounces+kmorel=sandia.gov at paraview.org
> [mailto:paraview-
> >>>> bounces+kmorel=sandia.gov at paraview.org] On Behalf Of Eric Monson
> >>>> Sent: Monday, February 04, 2008 10:11 AM
> >>>> To: ParaView List
> >>>> Subject: [Paraview] Temporal shift with Python Programmable Filter
> >>>>
> >>>> Hey All,
> >>>>
> >>>> This may seem like an odd question, but I think the answer may help
> >>>> clarify a larger problem I'm having...
> >>>>
> >>>> I'm trying to calculate the velocity vectors for diffusing
> >>>> particles,
> >>>> and the way I'm doing it right now is to feed two copies of my
> >>>> Unstructured Grid data into the Python Programmable Filter (PPF).
> >>>> The
> >>>> first copy has a time shift of 0, and the second one has Shift = 1.
> >>>> These are both Temporal Data Sets, and so I've been accessing the
> >>>> underlying Unstructured Grids by doing this:
> >>>>
> >>>> in0 = self.GetInputDataObject(0,0).GetDataSet(0,0)
> >>>> in1 = self.GetInputDataObject(0,1).GetDataSet(0,0)
> >>>>
> >>>> I force the PPF output to vtkUnstructuredGrid, and I have been
> >>>> making
> >>>> the output equivalent to one of the input points like so:
> >>>>
> >>>> out1 = self.GetOutput()
> >>>> out1.DeepCopy(in1)
> >>>>
> >>>> (In the complete calculation I later add a vtkFloatArray to "out1"
> >>>> containing the calculated velocity vectors.)
> >>>>
> >>>> The odd thing I see is that if the output is a copy of the Shift
> >>>> = 0
> >>>> point, I can increment time forward and backwards (arrow click on
> >>>> Time
> >>>> control) and everything looks fine. If the output is a copy of the
> >>>> Shift = 1 point, then on every other click it increments, and on
> >>>> the
> >>>> other clicks it doesn't move or change its scalar values. (If
> >>>> Shift =
> >>>> -1, then it increments properly backwards, but not forwards.)
> >>>>
> >>>> Is there some sort of update forcing I should be doing that I'm
> >>>> not?
> >>>> Is this an unreliable way of accessing the data from within the
> >>>> Temporal Data Sets?
> >>>>
> >>>> (I seemingly randomly get cases where my calculated velocity vector
> >>>> goes to zero and won't snap out of it unless I rebuild the whole
> >>>> pipeline from scratch, so I'm hoping I'm just doing something wrong
> >>>> here...)
> >>>>
> >>>> Thanks for the help,
> >>>> -Eric
> >>>>
> >>>> -----------------------------------------------------
> >>>> Eric E. Monson
> >>>> Duke Visualization Technology Group
> >>>>
> >>>>
> >>>> _______________________________________________
> >>>> ParaView mailing list
> >>>> ParaView at paraview.org
> >>>> http://www.paraview.org/mailman/listinfo/paraview
> >>>
> >>
> >
>
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