[Paraview-developers] vtkPVArraySelection and Exodus reader

[Karelitz, David B]

Yes, there is such a case in the Exodus Reader. The problem is we have a
hierarchical arrangement of blocks. A group of blocks is only on if all
of its blocks are on, and turning on/off an assembly means all of it's
blocks should be turned on/off. So if we have:

assembly X
	part 1
	part 2
	part 3 

All initially start turned on.

The user turns off part 1. If you send all of the events, then the
exodus reader receives an assembly X on and a part 1 off event.
Depending on the order of events, part 1 will be either on or off. The
even trickier case is that a part can be in multiple assemblies, so:

assembly X
	part 1
	part 2

assembly Y
	part 1
	part 2

Now the user turns off part 1 in assembly X. If the exodus reader
receives all the events, 3 separate events will affect part 1: assembly
X on, part 1 off, and assembly Y on. Again, the end result is determined
based on the order of events, and the order is not always
straightforward (i.e. just send them in list order).

The other feature of vtkPVArraySelection the exodus reader relies upon
is the vtkPVArraySelection reading back the values of all the arrays
from the reader after it makes all its changes. This relates to the fact
that if the user turns off part 1, then all assemblies using that part
show as deactivated in the reader.

Thanks,
Dave Karelitz

-----Original Message-----
From: paraview-developers-bounces+dbkarel=sandia.gov at paraview.org
[mailto:paraview-developers-bounces+dbkarel=sandia.gov at paraview.org] On
Behalf Of Utkarsh Ayachit
Sent: Monday, January 09, 2006 9:11 AM
To: paraview-developers at paraview.org
Subject: [Paraview-developers] vtkPVArraySelection and Exodus reader

This concerns the behaviour of the vtkPVArraySelection. Currently,
vtkPVArraySelection sets only the changes in the selection state on the
property: eg. if array1 and array2 were selected in previous Accept, and
the next time array2 was unselected, the value of the property at after
processing of the accept will be "array2 0".

The problem with this approach is that now the Server Manager state is
no longer a correct indication of the VTK object state for all the array
selection properties.

Berk thinks that the reason for the setting of changes on the property
is for the sake of the Exodus reader. The exodus reader has cases where
a selecting some array leads to selection/deselection of some other
array. We were wondering if anyone is aware of such a case with the
Exodus reader, and if it would break if we started setting all the
arrays' selection state on the property instead of merely the changes.

Thanks,
Utkarsh.
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