[Paraview] Memory explosion and strange behaviour -- Linux -- 'clip' -- 360 MB file needs 60 GB ??

[David E DeMarle]

On Tue, Jun 10, 2014 at 12:41 PM, Brian Corrie <bcorrie at sfu.ca> wrote:

> Hi All,
>
> I have one question regarding this conversation, as I have run into this
> issue before. It intrigues me as to why one can't clip a structured data
> set efficiently.
>
> http://www.paraview.org/pipermail/paraview/2012-December/026976.html
>
> The question I have is - does clip REALLY require all that memory - in my
> case it was a structured grid of 698x693x665 growing to in excess of 20 GB
> (see the question on the list above). That seems pretty excessive given the
> original size of the data set... I haven't done the math on the data set
> size of an unstructured data set, but 320MB to 20GB is a pretty big step.
>
>
Very likely.

imagedata
origin + extent + spacing ~= 36 bytes #(x,y,z + ni,nj,nk + sx,sy,sz) *
4bytes per word
(700^3 * 4)/(1024^3) = 1.27 GB #to store one scalar value on each point

unstructured grid
points array = (700^3 * 3 * 4)/(1024^3) = 3.8 GB #3=x,y,z, 4=4bytes per word
cellarray = (699^3 * 9 * 4)/*(1024^3) = 11.45GB, #1 numverts + 8 vertex
index
celltype = (699^3 * 4)/(1024^3) = 1.27GB
celllink = (700^3*9*4)/(1024^3) = 11.5GB #1 numcells + 8 using cells per
vert
(700^3 * 4)/(1024^3) = 1.27 GB #to store one scalar value on each point

(Someone check me on all of that please).

But yes, a clip like widget to something like Extract Subset that is easy
to use AND preserves the data type would be a really nice thing to have in
ParaView.
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