[Paraview] RE: [vtk-developers] xdmf questions (UNCLASSIFIED)

[Clarke, Jerry (Civ, ARL/CISD)]

Classification:  UNCLASSIFIED 
Caveats: NONE

John,

I am currently adding a time facility to Xdmf. 
I'll update the wiki @ xdmf.org when I am finished
but basically time will be an additional element
which is a child of Grid. In simplest form :

<Grid GridType="Uniform" ...
     <Time Value="0.1" />

There is an XdmfTime object. time->GetTimeType() will return
XDMF_TIME_SINGLE in the above example. Others are :

#define XDMF_TIME_SINGLE    0x00
#define XDMF_TIME_UNIFORM   0x01
#define XDMF_TIME_HYPERSLAB 0x02
#define XDMF_TIME_FUNCTION  0x03

More complex :
<Grid  GridType="Collection" ....
             <Time TimeType="Uniform">
                 <DataItem Format="XML" Dimensions="5" DataType="Float">
                     1.1 2.2 3.3 4.4 5.5
                 </DataItem>
             </Time>
Both of these are working, as is :
	<Time Function="???" />
the time object doesn't do anything with it yet other than return a
string.

Here's some python from the test :

print 'Time Type = ', tt, ' : ', t.GetTimeTypeAsString() if(tt ==
XDMF_TIME_SINGLE) :
     print 'Time = ', t.GetValue()
     t.SetValue(99.0)
elif(tt == XDMF_TIME_FUNCTION) :
     print 'Function = ', t.GetFunction()
     t.SetFunction('Hello')
     print 'Function = ', t.GetFunction()
elif(tt == XDMF_TIME_UNIFORM) :
     a = t.GetArray()
     print 'Values = ', a.GetValues()
     a.SetValueFromFloat64(3, 99.0)

t.Build()
print t.Serialize()

 

-----Original Message-----
From: vtk-developers-bounces+clarke=arl.army.mil at vtk.org
[mailto:vtk-developers-bounces+clarke=arl.army.mil at vtk.org] On Behalf Of
John Biddiscombe
Sent: Wednesday, January 23, 2008 11:17 AM
To: paraview at paraview.org; vtk-developers
Subject: [vtk-developers] xdmf questions

I am aware that others (who?) are working with xdmf and I have two
specific questions I'd like to ask before diving in to make changes to
read/writers

1) Has anyone given any consideration to time representation withing
xdmf. Specifically, multiple time steps and the ongoing time support in
vtk/paraview I need to store multiple time steps preferably in the same
file, but if one step per hdf5 file could be referenced from the xdmf
xml that's be ok I suppose. I don't see ant references to TIME_etc vars
in the code. 
If this is in development please let me know so that I can avoid
duplication.

2) Data spaces and parallel write. I'd like to modify the xdmf writer to
allow me to write pieces of volume data one by one  and specify the
extents so that 8/16/64 blocks etc could be written into a single file.
Has anyone started work on this? I wuld again like to avoid duplication.

Many thanks

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


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