# Value error in chains for a gaussian process

**URL:** https://discourse.pymc.io/t/value-error-in-chains-for-a-gaussian-process/9894
**Category:** v5
**Created:** [July 13, 2022, 1:07pm UTC](https://discourse.pymc.io/t/value-error-in-chains-for-a-gaussian-process/9894 "2022-07-13T13:07:50Z")
**Posts on this page:** 1
**Showing post:** 4

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### Author: ![OriolAbril](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/oriolabril/32/2497_2.png) [@OriolAbril](https://discourse.pymc.io/u/OriolAbril)
#### Post date: [July 15, 2022, 9:53am UTC](https://discourse.pymc.io/t/value-error-in-chains-for-a-gaussian-process/9894/4 "2022-07-15T09:53:06Z")

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If I can add to the conversation, **do not use the `samples` argument in v4**. The plan is to remove it, see [Remove `samples` and `keep_size` from posterior\_predictive · Issue #5775 · pymc-devs/pymc · GitHub](https://github.com/pymc-devs/pymc/issues/5775). If you want to generate posterior predictive samples for a subset of the posterior only, you should provide a sliced posterior to `sample_posterior_predictive` as shown in the api docs example (bottom of the page): [pymc.sample\_posterior\_predictive — PyMC 4.1.2 documentation](https://www.pymc.io/projects/docs/en/stable/api/generated/pymc.sample_posterior_predictive.html)

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