# LKJCorr parameters

**URL:** <https://discourse.pymc.io/t/lkjcorr-parameters/9680>\
**Category:** General\
**Created:** [June 18, 2022, 2:32pm UTC](https://discourse.pymc.io/t/lkjcorr-parameters/9680 "2022-06-18T14:32:38Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![v\_p](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/v_p/32/5249_2.png) [@v\_p](https://discourse.pymc.io/u/v_p)\
**Post date:** [June 18, 2022, 2:32pm UTC](https://discourse.pymc.io/t/lkjcorr-parameters/9680/1 "2022-06-18T14:32:39Z")

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I am trying to use a line of example code

```auto
C_triu = pm.LKJCorr('C_triu', n=2, p=2)

```

but when i check out the JKJCorr API page it says JKJCorr parameters are n and eta. What is the parameter p that is passed in the above line of code?  
Thank you

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**Author:** ![ricardoV94](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/ricardov94/32/5775_2.png) [@ricardoV94](https://discourse.pymc.io/u/ricardoV94)\
**Post date:** [June 18, 2022, 7:49pm UTC](https://discourse.pymc.io/t/lkjcorr-parameters/9680/2 "2022-06-18T19:49:25Z")

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Where did you get that example with `p`?

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<div class="post-metadata">

**Author:** ![v\_p](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/v_p/32/5249_2.png) [@v\_p](https://discourse.pymc.io/u/v_p)\
**Post date:** [June 18, 2022, 9:58pm UTC](https://discourse.pymc.io/t/lkjcorr-parameters/9680/3 "2022-06-18T21:58:04Z")

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I didn’t bookmark it. Overflow maybe. That’s the piece of code. Someone was trying to modify the radon set example.

```auto
C_triu = pm.LKJCorr('C_triu', n=2, p=2)
    C = tt.fill_diagonal(C_triu[np.zeros((2,2), 'int')], 1.)
    sigma_diag = tt.nlinalg.diag(sigma)
    cov = tt.nlinalg.matrix_dot(sigma_diag, C, sigma_diag)
    tau = tt.nlinalg.matrix_inverse(cov)

    ab = pm.MvNormal('ab', mu=mu, tau=tau, shape=(n_counties, 2))

```

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<div class="post-metadata">

**Author:** ![ricardoV94](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/ricardov94/32/5775_2.png) [@ricardoV94](https://discourse.pymc.io/u/ricardoV94)\
**Post date:** [June 19, 2022, 6:26am UTC](https://discourse.pymc.io/t/lkjcorr-parameters/9680/4 "2022-06-19T06:26:54Z")

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It could be that the paramrter used to be called `p` and was later renamed to `eta`, or that it use to do something else and was then removed in favor of eta.

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<div class="post-metadata">

**Author:** ![v\_p](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/v_p/32/5249_2.png) [@v\_p](https://discourse.pymc.io/u/v_p)\
**Post date:** [June 19, 2022, 4:05pm UTC](https://discourse.pymc.io/t/lkjcorr-parameters/9680/5 "2022-06-19T16:05:03Z")

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Ok, thank you for your reply.

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<div class="post-metadata">

**Author:** ![v\_p](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/v_p/32/5249_2.png) [@v\_p](https://discourse.pymc.io/u/v_p)\
**Post date:** [June 19, 2022, 5:37pm UTC](https://discourse.pymc.io/t/lkjcorr-parameters/9680/6 "2022-06-19T17:37:59Z")

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It still works as p parameter though. If I run the code it executes this piece as is.

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<div class="post-metadata">

**Author:** ![ricardoV94](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/ricardov94/32/5775_2.png) [@ricardoV94](https://discourse.pymc.io/u/ricardoV94)\
**Post date:** [June 19, 2022, 5:38pm UTC](https://discourse.pymc.io/t/lkjcorr-parameters/9680/7 "2022-06-19T17:38:53Z")

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What version of PyMC are you using?

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<div class="post-metadata">

**Author:** ![v\_p](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.pymc.io/v_p/32/5249_2.png) [@v\_p](https://discourse.pymc.io/u/v_p)\
**Post date:** [June 19, 2022, 6:40pm UTC](https://discourse.pymc.io/t/lkjcorr-parameters/9680/8 "2022-06-19T18:40:51Z")

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I am using ‘3.11.5’.