# Slow Programmable Filter

**URL:** https://discourse.paraview.org/t/slow-programmable-filter/3848
**Category:** ParaView Support
**Created:** [March 19, 2020, 7:24pm UTC](https://discourse.paraview.org/t/slow-programmable-filter/3848 "2020-03-19T19:24:13Z")
**Posts on this page:** 1
**Showing post:** 13

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### Author: ![woodscn](https://discourse.paraview.org/user_avatar/discourse.paraview.org/woodscn/32/3226_2.png) [@woodscn](https://discourse.paraview.org/u/woodscn)
#### Post date: [March 20, 2020, 4:47pm UTC](https://discourse.paraview.org/t/slow-programmable-filter/3848/13 "2020-03-20T16:47:36Z")

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I put together an example using Wavelet.

Is the `where` function not implemented fully? I got errors testing on the Wavelet source that it only accepted 1 positional argument.

I’m also having trouble accessing the `outer` methods of functions. Those should be present for numpy ufuncs, and they cause the function to compute on all pairs of values from the input arrays, rather than element-wise. Various work-arounds are slow.

[ForKitware.pvsm](https://discourse.paraview.org/uploads/short-url/ciLeADhvWRYktgTp2xdSY6Tb2KD.pvsm) (606.6 KB)

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