Hello everybody,

Is there a way to retrieve the tuned hyperparameters for the base HMC sampler (stepsize, Mass-matrix) and for the NUTS sampler (Mass matrix) after the sampling?

I greatly appreciate your help!

Thanks,

Kevin

You can access the mass matrix if you manually create the step method, and don’t use the parallel sampler by setting `cores=1`

:

```
import pymc as pm
with pm.Model() as model:
pm.Normal("alpha")
step = pm.NUTS()
pm.sample(step=step, cores=1, chains=1)
step.potential._stds
```

If you sample using nutpie, you can also store the current mass matrix in the sampler stats:

```
compiled = nutpie.compile_pymc_model(model)
tr = nutpie.sample(compiled, store_mass_matrix=True)
tr.warmup_sample_stats.mass_matrix_inv
```

The stepsize is always stored in the sample_stats.

1 Like

Thank you very much!