[Paraview] question-filter

Wed Mar 16 21:03:54 EDT 2016

Hey Cory,
I tried the expression sum(alpha*volume(input)), I got an error saying that alpha is not defined. I changed the expression to sum(alpha.water*volume(input)) because the water fraction  is written in file alpha.water but again I got the same errors. You find attached snapshots that illustrate that.
Regards,Islem 

    Le Mercredi 16 mars 2016 14h29, Cory Quammen <cory.quammen at kitware.com> a écrit :

 Yes!
Assuming your cell fraction is cell data named "alpha", use the following expression in your annotation filter:
sum(alpha*volume(input))
Make sure you set the Array Association property to Cell Data.
Let me know if that works or not.
Thanks,Cory
On Wed, Mar 16, 2016 at 8:56 AM, Megdich Islem <megdich_islem at yahoo.fr> wrote:

Hey Cory,
Thank you for your email. Can I get some hints about how can I multiply each cell volume with  the water fraction. 
Regards,Islem MegdichePhD student  

    Le Mercredi 16 mars 2016 12h38, Cory Quammen <cory.quammen at kitware.com> a écrit :

 Islem,
Thanks for reporting back which worked. I'm not sure why the expression without the "algs." doesn't work - in any case, I'm glad it is working for you now.
The "inputs[0]" simply means the first element in the inputs list. The index lets you pick the input (there can be more than one). You could also simply use "input", which gives you the same element as "inputs[0]".
Cory
On Tue, Mar 15, 2016 at 7:01 AM, Megdich Islem <megdich_islem at yahoo.fr> wrote:

Hi Cory,
Thank you for your email. I tried that example sphere source -> Delaunay3D -> Python Annotation filter and it works fine. I set the python expression to  algs.sum(algs.volume(inputs[0])) and then to sum(volume(inputs[0])) and it works in both cases. The type from the information panel is Table.
But, it turns out that for my case the problem is with the Python expression, when I use this expression algs.sum(algs.volume(inputs[0])) I get errors while this expression sum(volume(inputs[0])) solves the problem. The type from the information panel is Table.
Can I ask what does inputs[0] mean in the python expression. I have no background in python, that's why the expression seems odd to me.
Regards,Islem Megdiche 

    Le Lundi 14 mars 2016 15h04, Cory Quammen <cory.quammen at kitware.com> a écrit :

 One more thing: you should be able to change the Python expression to
sum(volume(inputs[0]))
On Mon, Mar 14, 2016 at 10:09 AM, Cory Quammen <cory.quammen at kitware.com> wrote:

Hi Islem,
Sorry for the late reply. I've been swamped lately.
Thank you for the detailed explanation of what you are doing. That really helps us narrow down what might be going on.
I'm not sure what the problem is. I have a simple pipeline example where this works:
Sphere source -> Delaunay3D -> Python Annotation filter
The Delaunay3D filter produces an unstructured grid, from which I am able to get the volumes.
I suspect ParaView readds your OpenFOAM data set as a multiblock data set? Could you look at the Info panel and report it's Type. It should be the first item under the "Statistics" sub-section.
If it is indeed a multiblock data set, please try this:
Place a MergeBlocks filter between your Threshold filter and Python Annotation filter.
Please see if that works. If it does, we'll move on to multiplying the volume by the water fraction.
Thanks,Cory
On Tue, Mar 8, 2016 at 6:35 AM, Megdich Islem <megdich_islem at yahoo.fr> wrote:

Hi cory, I was working on the case of water computationin the desired domain taking into account your suggestions. I attached heresome pictures that helps to figure out how I did it. I created the domain inwhich I want to compute the volume of water using the clip filter and then Ithresolded the clipped domain to  contain only the cells ranging between0.5 and 1 of alpha water and I ended up with the domain illustrated in picture3, and then I applied the annotation filter setting up the array association toPoint Data and the expression to algs.sum(algs.volume(inputs[0])), but I endedup with an error in the render view and output message stating thatAttributeError:'None Type' object has no attribute 'GetCellData'. I couldn'tunderstand the reason, I tried  all the array Association options, I gotthe same error, except for the Row Data, I got this error:AttributeError:'NoneType' object has no attribute 'GetNumberOfArrays'.(picture 4 and 5). I googled that link  paraview.simple.PythonAnnotation — ParaView/Python5.0.1-RC1-193-gad11756 documentation

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|  paraview.simple.PythonAnnotation — ParaView/Python 5.0.1-RC1-193-gad11756 documentation Docs » Index paraview.simple.PythonAnnotation paraview.simple.PythonAnnotation paraview.simple.PythonAnnotation(*input, **params) This filter uses Python to calculate an expression. It  |  |
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|  Afficher sur www.paraview.org  |  Aperçu par Yahoo  |  |
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 It  says that I need to set the input whichI didn't know how to do it since it doesn't ask for any input in the PropertiesPanel. Any solutions for this problem ?? In this expression algs.sum(algs.volume(inputs[0])), whatdoes the 0  stands for ?   I think if I threshold the domain in which Iwant to calculate the volume of water, let's say between 0.5 and 1, then I willend up by inaccurate water volume because I am including volume of air in thecomputed volume and on the other hand I am ignoring the cells that contain lessthan 0.5 of water. That's why, I am looking for an algorithm that multiplyevery cell containing water by the coefficient alpha water. You find attachedin picture 6, an example of how I want to calculate the water volume. I don'tknow how to program it. Any helps concerning this matter will be verymuch appreciated.Regards,Islem MegdichePhD student

    Le Mardi 23 février 2016 14h21, Cory Quammen <cory.quammen at kitware.com> a écrit :

 Hi Islem,

Please reply-all to keep the discussion on the list so that others may
benefit from the discussion.

First, is there a data array that describes whether a volume element
in your mesh contains water or some other element? If so, you can use
the Threshold filter under the Filters -> Alphabetical -> Threshold
menu to select only the elements representing water. You will have to
set the minimum and maximum to the value that represents water, then
click Apply.

HTH,
Cory

On Mon, Feb 22, 2016 at 1:14 PM, Megdich Islem <megdich_islem at yahoo.fr> wrote:
> Hi again,
>
> Thank you for your suggestion, Could you please explain how to do the first
> step because I am not the one who created the picture I sent you before.
>
> Regards,
> Islem
>
>
> Le Lundi 22 février 2016 16h45, Megdich Islem <megdich_islem at yahoo.fr> a
> écrit :
>
>
> Thank you for your reply. I will try your suggestions.
>
> Regards,
> Islem
>
>
> Le Lundi 22 février 2016 14h22, Cory Quammen <cory.quammen at kitware.com> a
> écrit :
>
>
> Islem,
>
> There are likely two steps:
>
> 1). Threshold your volume to identify only the water-containing cells.
> It looks like you have a way to do this already?
>
> 2). Compute the volumes of the water-containing cells and summing them up.
>
> You can use the Threshold filter to do number 1 if you have a material
> code in the cell data. To compute the volume of the cells, add a
> Python Annotation filter to the Threshold filter. Set the Expression
> to
>
> algs.sum(algs.volume(inputs[0]))
>
> This uses the numpy-like interface in the Python layer to compute the
> volumes of the cells and sum them all up. The Python Annotation filter
> should display the volume with a text label in your renderer.
>
> Hope this helps,
> Cory
>
> On Mon, Feb 22, 2016 at 9:09 AM, Megdich Islem <megdich_islem at yahoo.fr>
> wrote:
>> Hi Cory,
>>
>> Thank you very much for your prompt reply. I've attached here a picture
>> that
>> illustrates my problem. I am working on the break of bund walls and I want
>> to compute the volume of water that overtops the bund wall (walls
>> surrounding storage tank), after the  solution reaches the steady state.
>>
>> Regards,
>> Islem
>>
>>
>> Le Lundi 22 février 2016 13h53, Cory Quammen <cory.quammen at kitware.com> a
>> écrit :
>>
>>
>> Hi Islem,
>>
>> This is the place to ask ParaView questions! There is some activity on
>> StackOverflow, but most people ask questions on this mailing list.
>>
>> Could you clarify what you want to compute? Do you just want to subset
>> a volume mesh and display the results over time? Do you want to
>> compute one quantity and display it as a graph over time? Do you want
>> to compute a single number from a time series data set?
>>
>> Thanks,
>> Cory
>>
>> On Mon, Feb 22, 2016 at 8:48 AM, Megdich Islem <megdich_islem at yahoo.fr>
>> wrote:
>>> Hello,
>>>
>>> I am new to paraview, and I didn't find a forum under paraview website to
>>> ask my question.
>>> My question is is there any filter in paraview that lets to compute the
>>> evolution of a quantity within a specific volume of the mesh.
>>>
>>> Regards,
>>> Islem
>>>
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>>
>>
>> --
>> Cory Quammen
>> R&D Engineer
>> Kitware, Inc.
>
>>
>>
>>
>
>
>
> --
> Cory Quammen
> R&D Engineer
> Kitware, Inc.
>
>
>
>

-- 
Cory Quammen
R&D Engineer
Kitware, Inc.

-- 
Cory Quammen
R&D Engineer
Kitware, Inc.

-- 
Cory Quammen
R&D Engineer
Kitware, Inc.

-- 
Cory Quammen
R&D Engineer
Kitware, Inc.

-- 
Cory Quammen
R&D Engineer
Kitware, Inc.

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