# Changes In ITK Mattes Mutual Information Metric

**URL:** https://discourse.itk.org/t/changes-in-itk-mattes-mutual-information-metric/2353
**Category:** Algorithms
**Tags:** implementation, c, mutual-information
**Created:** [October 26, 2019, 9:47pm UTC](https://discourse.itk.org/t/changes-in-itk-mattes-mutual-information-metric/2353 "2019-10-26T21:47:19Z")
**Posts on this page:** 1
**Showing post:** 17

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### Author: ![dzenanz](https://discourse.itk.org/user_avatar/discourse.itk.org/dzenanz/32/1093_2.png) [@dzenanz](https://discourse.itk.org/u/dzenanz)
#### Post date: [November 12, 2019, 3:19pm UTC](https://discourse.itk.org/t/changes-in-itk-mattes-mutual-information-metric/2353/17 "2019-11-12T15:19:56Z")

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v4 classes are mostly in [Registration/Metricsv4](https://github.com/InsightSoftwareConsortium/ITK/tree/master/Modules/Registration/Metricsv4/include), while v3 classes are mostly in [Registration/Common](https://github.com/InsightSoftwareConsortium/ITK/tree/master/Modules/Registration/Common/include). There was no significant registration refactoring between ITKv4 and ITKv5. But registration was affected by [multi-threading refactoring](https://discourse.itk.org/t/multi-threader-refactoring/840) done in v5 [[migration guide](https://github.com/InsightSoftwareConsortium/ITK/blob/master/Documentation/ITK5MigrationGuide.md#multithreading-refactored)].

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_[View the full topic](https://discourse.itk.org/t/changes-in-itk-mattes-mutual-information-metric/2353)._