[vtkusers] Array order in VTK?

[Elvis Stansvik]

2016-09-19 17:28 GMT+02:00 Berk Geveci <berk.geveci at kitware.com>:
> One thing that makes things a bit confusing is that, in the case of vectors,
> the fastest growing is the vector component. So something like this:
>
> (0, 0, 0) u, (0, 0, 0) v, (0, 0, 0) w, (1, 0, 0) u, (1, 0, 0) v, (1, 0, 0) w
>
> This makes it a hybrid Fortran and C. Which is pain when mapping these to
> numpy arrays :-)

Ah. Thankfully working only with single component data so far, but
thanks for the heads up Berk :)

Elvis

>
> -berk
>
> On Mon, Sep 19, 2016 at 9:51 AM, Elvis Stansvik
> <elvis.stansvik at orexplore.com> wrote:
>>
>> 2016-09-19 15:24 GMT+02:00 Cory Quammen <cory.quammen at kitware.com>:
>> > Elvis,
>> >
>> > VTK image data arrays are stored such that the X dimension increases
>> > fastest, followed by Y, followed by Z.
>> > Concrete example where dimensions of the image are XDIM, YDIM, ZDIM:
>> >
>> > Array index : i,j,k indices
>> > 0 : (0, 0, 0)
>> > 1 : (1, 0, 0)
>> > 2 : (2, 0, 0)
>> > ...
>> > XDIM : (0, 1, 0)
>> > XDIM+1 : (1, 1, 0)
>> > XDIM+2 : (2, 1, 0)
>> > ...
>> > XDIM*YDIM : (0, 0, 1)
>> > XDIM*YDIM + 1 : (1, 0, 1)
>> >
>> > So I guess that is Fortran order?
>>
>> Right, thanks for the clarification Cory.
>>
>> Elvis
>>
>> >
>> > HTH,
>> > Cory
>> >
>> > On Mon, Sep 19, 2016 at 1:40 AM, Elvis Stansvik
>> > <elvis.stansvik at orexplore.com> wrote:
>> >> Hi all,
>> >>
>> >> This is a simple question: I haven't been able to find any info on
>> >> whether arrays (images, ...) are stored in row major (C) or column
>> >> major (Fortran) order in VTK.
>> >>
>> >> I assumed they are in C order, but then I saw this blog post:
>> >>
>> >>
>> >> https://blog.kitware.com/developing-hdf5-readers-using-vtkpythonalgorithm/
>> >>
>> >> In a comment the author says
>> >>
>> >>     # Note that we flip the dimensions here because
>> >>     # VTK's order is Fortran whereas h5py writes in
>> >>     # C order. We don't want to do deep copies so we write
>> >>     # with dimensions flipped and pretend the array is
>> >>     # C order.
>> >>
>> >> which made me a little unsure. What is the array order of the data
>> >> classes in VTK, and is it the same for all classes?
>> >>
>> >> Thanks,
>> >> Elvis
>> >> _______________________________________________
>> >> Powered by www.kitware.com
>> >>
>> >> Visit other Kitware open-source projects at
>> >> http://www.kitware.com/opensource/opensource.html
>> >>
>> >> Please keep messages on-topic and check the VTK FAQ at:
>> >> http://www.vtk.org/Wiki/VTK_FAQ
>> >>
>> >> Search the list archives at: http://markmail.org/search/?q=vtkusers
>> >>
>> >> Follow this link to subscribe/unsubscribe:
>> >> http://public.kitware.com/mailman/listinfo/vtkusers
>> >
>> >
>> >
>> > --
>> > Cory Quammen
>> > Staff R&D Engineer
>> > Kitware, Inc.
>> _______________________________________________
>> Powered by www.kitware.com
>>
>> Visit other Kitware open-source projects at
>> http://www.kitware.com/opensource/opensource.html
>>
>> Please keep messages on-topic and check the VTK FAQ at:
>> http://www.vtk.org/Wiki/VTK_FAQ
>>
>> Search the list archives at: http://markmail.org/search/?q=vtkusers
>>
>> Follow this link to subscribe/unsubscribe:
>> http://public.kitware.com/mailman/listinfo/vtkusers
>
>