[Paraview] [xdmf] - vtkXdmfReader - time support

[John Biddiscombe]

I've just checked in some changes to the vtkXdmfReader for handling time 
dependent data.

I have also uploaded a test dataset to here
ftp://ftp.cscs.ch/out/biddisco/xdmf

this contains a single Volume of dimension {24,24,24} with several 
scalar/vector fields.
Interesting Vector fields are
    X-Vector {1, 0, 0}
    Y-Vector {0, 1, 0}
    Z-Vector {0, 0, 1}
which makes it ideal for testing. Some other fields are block number and 
suchlike which are only useful to me.

In the Xdmf xml file, the same data is referenced twice - so there are 
two time steps - they are actually the same data in both time steps, but 
the second step swaps the x,y,z vector fields around by simple changing 
the string references to datasets in the hdf5 file.

In timestep 0 (time value 0.0)
x - X
y - Y
z - Z
In timestep 1 (time value 0.2)
x - Y
y - Z
z - X

The changes I have made to the XdmfReader might break some code since I 
had to change the Grid storage from a Map structure to a vector - to 
allow the same grid name to be used for multiple time steps. There are 
also many other small tweaks/fixes all over the place.

I will check in some changes to the vtkXdmfWriter later, but will post 
separately on that.

Please let me know of any problems this introduces - I think there is 
still much work to be done (c.f. other vtk data types)

JB

-- 
John Biddiscombe,                            email:biddisco @ cscs.ch
http://www.cscs.ch/about/BJohn.php
CSCS, Swiss National Supercomputing Centre  | Tel:  +41 (91) 610.82.07
Via Cantonale, 6928 Manno, Switzerland      | Fax:  +41 (91) 610.82.82