BUG: No Progressbar in Marimo Notebook with ADVI
Author: MathisC22Created Aug 21, 2026Updated Aug 23, 2026
Labelsbug
Describe the issue:
Hello there,
I recently switched to Marimo notebooks and noticed that I do not get any progress bar during the fitting process itself. Instead, it only appears after the fitting is over. I glanced over #8055, but it looks like this was just about pm.sample().
As you can see in the screenshot, the cell is running for over 11 seconds now and no progress bar shows up, unfortunately.
Reproduceable code example:
import marimo as mo
import numpy as np
import pymc as pm
print("pymc version:", pm.__version__)
print("marimo version:", mo.__version__)
rng = np.random.default_rng(0)
y = rng.normal(loc=3.0, scale=1.0, size=200)
with pm.Model() as model:
mu = pm.Normal("mu", mu=0, sigma=10)
sigma = pm.HalfNormal("sigma", sigma=10)
pm.Normal("obs", mu=mu, sigma=sigma, observed=y)
# Expected: an ADVI progress bar should render here.
# Actual: no progress bar is shown in the marimo notebook cell output during fitting, it only appears after its done.
approx = pm.fit(n=500_000, method="advi")Error message:
PyMC version information:
pymc version: 6.3.1 marimo version: 0.24.0
Context for the issue:
No response
Source: pymc-devs/pymc