# What is rescor in {brms} doing for this non-linear multivariate model

**URL:** <https://discourse.mc-stan.org/t/what-is-rescor-in-brms-doing-for-this-non-linear-multivariate-model/40677>\
**Category:** brms\
**Tags:** brms\
**Created:** [November 23, 2025, 11:03pm UTC](https://discourse.mc-stan.org/t/what-is-rescor-in-brms-doing-for-this-non-linear-multivariate-model/40677 "2025-11-23T23:03:12Z")\
**Posts on this page:** 1\
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**Author:** ![amynang](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/amynang/32/19114_2.png) [@amynang](https://discourse.mc-stan.org/u/amynang)\
**Post date:** [November 24, 2025, 5:34pm UTC](https://discourse.mc-stan.org/t/what-is-rescor-in-brms-doing-for-this-non-linear-multivariate-model/40677/2 "2025-11-24T17:34:10Z")

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Hi Ben,

I’m afraid my answer to that other question was misleading, because it results in estimating two parameters (in the current version of your model `alpha_ar` and `d15n_ar`), while what you want is to estimate a\_r jointly from the two formulas.

I think this is currently not possible in `brms` but you could modify the generated Stan code to achieve it.

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