# Perplexity of a model

**URL:** <https://discourse.pymc.io/t/perplexity-of-a-model/25>\
**Category:** Questions\
**Tags:** from\_github\
**Created:** [June 13, 2017, 1:19pm UTC](https://discourse.pymc.io/t/perplexity-of-a-model/25 "2017-06-13T13:19:34Z")\
**Posts on this page:** 2\
**Page:** 2

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**Author:** ![ferrine](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/ferrine/32/10_2.png) [@ferrine](https://discourse.pymc.io/u/ferrine)\
**Post date:** [June 29, 2017, 8:49am UTC](https://discourse.pymc.io/t/perplexity-of-a-model/25/21 "2017-06-29T08:49:02Z")

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Defining tracker beforehand gives your a reference to it

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**Author:** ![pwl](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/pwl/32/212_2.png) [@pwl](https://discourse.pymc.io/u/pwl)\
**Post date:** [June 29, 2017, 8:54am UTC](https://discourse.pymc.io/t/perplexity-of-a-model/25/22 "2017-06-29T08:54:07Z")

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Right, now I know what you meant. I just wrote it this way to make this particular test case shorter.

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