# Numpyro sampler issue

**URL:** <https://discourse.pymc.io/t/numpyro-sampler-issue/16497>\
**Category:** version agnostic\
**Tags:** jax\
**Created:** [February 5, 2025, 4:05am UTC](https://discourse.pymc.io/t/numpyro-sampler-issue/16497 "2025-02-05T04:05:02Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![leadhopper](https://avatars.discourse-cdn.com/v4/letter/l/c68b51/32.png) [@leadhopper](https://discourse.pymc.io/u/leadhopper)\
**Post date:** [February 5, 2025, 4:05am UTC](https://discourse.pymc.io/t/numpyro-sampler-issue/16497/1 "2025-02-05T04:05:02Z")

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In executing MCMC, if you specify nuts\_sampler=“numpyro”, the following error occurs:  
“NotImplementedError: jax.experimental.host\_callback has been deprecated since March 2024 and is now no longer supported. See [Deprecate jax.experimental.host\_callback in favor of JAX external callbacks · Issue #20385 · jax-ml/jax · GitHub](https://github.com/jax-ml/jax/issues/20385)”  
It appears that this issue is due to changes in JAX. What should be done to address this?

The code is below. X is iris data.

```py
model1 = pm.Model()
with model1:
    mu = pm.Normal('mu', mu=0.0, sigma=10.0)
    sigma = pm.HalfNormal('sigma', sigma=10.0)
    X_obs = pm.Normal('X_obs', mu=mu, sigma=sigma, observed=X)

with model1:
    idata1 = pm.sample(
    chains=4,
    tune=1000,
    draws=1000,
    nuts_sampler="numpyro",
    random_seed=123)

```

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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:** [February 5, 2025, 6:28am UTC](https://discourse.pymc.io/t/numpyro-sampler-issue/16497/2 "2025-02-05T06:28:31Z")

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Try to install an older version of jax and jaxlib? Probably numpyro have to update to the Jax changes