# Write mixed element function to files

**URL:** <https://fenicsproject.discourse.group/t/write-mixed-element-function-to-files/12837>\
**Category:** I/O\
**Created:** [November 23, 2023, 1:32pm UTC](https://fenicsproject.discourse.group/t/write-mixed-element-function-to-files/12837 "2023-11-23T13:32:25Z")\
**Posts on this page:** 1\
**Showing post:** 11

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**Author:** ![dokken](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/dokken/32/1560_2.png) [@dokken](https://fenicsproject.discourse.group/u/dokken)\
**Post date:** [November 27, 2023, 2:57pm UTC](https://fenicsproject.discourse.group/t/write-mixed-element-function-to-files/12837/11 "2023-11-27T14:57:10Z")

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> [@jegor.kravchenko](#):
>
> I am not quite sure what I changed, so I add a new code snippet. Apparently passing `"BP4"` as an engine to the VTXWriter helps to open the file in paraview.

ADIOS2 has started to use `bp5` as the default bp format. This is not supported by Paraview yet, see: [Paraview opens ADIOS2-VTX BP5 files as BP4 (#22108) · Issues · ParaView / ParaView · GitLab](https://gitlab.kitware.com/paraview/paraview/-/issues/22108)

> [@jegor.kravchenko](#):
>
> When I open the bp Folder in paraview, it seems like I need to tell it how to read my file? What I basically get is the following error:
> 
> ```auto
> ERROR: In vtkADIOS2CoreImageReader.cxx, line 648
> vtkADIOS2CoreImageReader (00000131155E33C0): Can not use the dimension of array Num
> 
> ```

This is not the correct adios2 reader, as it should point to the correct image reader:

 ![image](https://global.discourse-cdn.com/free1/uploads/fenicsproject1/original/2X/6/67992435270affcf2d05f80f573e529852c044a1.png)

and for  
For `FidesWriter` one should use

 ![image](https://global.discourse-cdn.com/free1/uploads/fenicsproject1/original/2X/2/2032509d59451fa8dec968edcd4cabe53f5ac224.png)

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