# vtkMultiBlockDataSet and parallel pipelines

**URL:** https://discourse.vtk.org/t/vtkmultiblockdataset-and-parallel-pipelines/3137
**Category:** Support
**Created:** [April 23, 2020, 8:44pm UTC](https://discourse.vtk.org/t/vtkmultiblockdataset-and-parallel-pipelines/3137 "2020-04-23T20:44:38Z")
**Posts on this page:** 1
**Showing post:** 2

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### Author: ![utkarshayachit](https://discourse.vtk.org/user_avatar/discourse.vtk.org/utkarshayachit/32/379_2.png) [@utkarshayachit](https://discourse.vtk.org/u/utkarshayachit)
#### Post date: [April 24, 2020, 2:44pm UTC](https://discourse.vtk.org/t/vtkmultiblockdataset-and-parallel-pipelines/3137/2 "2020-04-24T14:44:21Z")

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> [@scotsman60](#):
>
> Is my assumption that the above filters can be run in parallel across the blocks of a MultiBlockDataSet valid or not?

Not by default. However, there’s an experiemental executive that supported this. If you set the `vtkThreadedCompositeDataPipeline` as the default executive using `vtkAlgorithm::SetDefaultExecutivePrototype` and then the executive will execute the algorithm on each block in parallel. I say it’s experimental since I am not aware how well tested/used this executive is.

> [@scotsman60](#):
>
> It seems that I cannot pass the MultiBlockDataSet directly to any mapper

Better option is to use `vtkCompositePolyDataMapper2` instead. It avoids merging all blocks into one.

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