# Divergent transitions - a primer

**URL:** <https://discourse.mc-stan.org/t/divergent-transitions-a-primer/17099>\
**Category:** General\
**Tags:** howto, divergences\
**Created:** [July 30, 2020, 11:42am UTC](https://discourse.mc-stan.org/t/divergent-transitions-a-primer/17099 "2020-07-30T11:42:35Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![martinmodrak](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/martinmodrak/32/133_2.png) [@martinmodrak](https://discourse.mc-stan.org/u/martinmodrak)\
**Post date:** [August 3, 2020, 7:22pm UTC](https://discourse.mc-stan.org/t/divergent-transitions-a-primer/17099/4 "2020-08-03T19:22:54Z")

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I remembered @andre.pfeuffer, @tlyim had some useful points in an older threads: [N best tips & tricks (or the go-to checklist) for new Stan model builders? - #11 by andre.pfeuffer](https://discourse.mc-stan.org/t/n-best-tips-tricks-or-the-go-to-checklist-for-new-stan-model-builders/8688/11), [Top tips for beginner Stan users](https://discourse.mc-stan.org/t/top-tips-for-beginner-stan-users/10330)

Going to add those to the list. Happy if you correct me if you think something’s fishy

> [@N best tips & tricks (or the go-to checklist) for new Stan model builders?](https://discourse.mc-stan.org/t/n-best-tips-tricks-or-the-go-to-checklist-for-new-stan-model-builders/8688/3):
>
> - Use exponential / half-normal distribution instead of half-cauchy in case of problems with standarddev.
> - Check the problematic scaling of the mass-matrix given from Cmdstan. Adjust parameterization.
> - Run optimizing instead of NUTS to check if the values look reasonable, if not find out why.

> [@N best tips & tricks (or the go-to checklist) for new Stan model builders?](https://discourse.mc-stan.org/t/n-best-tips-tricks-or-the-go-to-checklist-for-new-stan-model-builders/8688/1):
>
> specify any known bounds of a parameter (thereby help Stan to pick the appropriate default prior, eg, uniform vs. normal)

**EDIT:** I actually don’t really understand the bit about the mass-matrix, would you care to add it (and preferable share a link to forum thread/other resource that has more details).

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