Pymc Mlflow

PyMC experiment tracking with MLflow

Record how a fit was produced, preserve its inference output, and retrieve it without changing the consuming project's modeling environment. pymc-mlflow is this skill's name; the optional integration module is pymc_marketing.mlflow, not a separate pymc-mlflow package.

Choose the integration

Examples target PyMC 6/DataTree and modern ArviZ. PyMC-Marketing 1.2.0 requires PyMC >=6.3.1,<6.4.0 and ArviZ >=1.2.0,<2.0; MLflow is a separate optional installation. Inspect installed versions and signatures before enabling integration. Do not downgrade or replace a working modeling environment just to use autologging. Direct MLflow tracking does not require PyMC-Marketing.

Preserve the fit before interpreting it

1. Identify the run. Set a tracking URI and project experiment. Log source/data identities, package versions, seed and actual sampler configuration. Use consistent lowercase tags for exploratory, reportable and mock runs; tags describe provenance, not proof of inferential quality.
2. Fit inside an explicit run. Use with mlflow.start_run(): so exceptions mark failed runs. Log configuration before expensive work. MLflow parameters cannot change within a run; do not overwrite integration-owned parameters such as likelihood, draws or chains with different values.
3. Persist actual inference. Save a local raw DataTree before diagnostics or enrichment. Generic pymc_marketing.mlflow.autolog() does not save idata.nc: explicitly serialize/upload it or call log_inference_data. Preserve the groups needed by the downstream task; adding likelihoods or predictions later requires saving the enriched output too.
4. Log diagnostics, not reassurance. Preserve chain identities and actual draws. Missing/nonfinite diagnostics are unresolved, not zero. A draw-count threshold, run tag or attractive summary is not convergence evidence. Use arviz-diagnostics for computation, predictive checks and reliable comparison.
5. Retrieve and check. Download artifacts through MLflow to local paths, reopen the DataTree, and check groups, coordinates and required variables. A remote artifact URI is not a local NetCDF filename.
6. Compare like with like. Numeric filtering uses metrics, not string parameters. Compare predictive scores only for the same response scale, observations and validation target; report uncertainty and Pareto-k warnings. Training PPCs are not predictions for held-out inputs.

Keep tracking distinct from serving

• A posterior NetCDF file is inference output, not an executable generic PyMC model, preprocessing pipeline or prediction endpoint.
• PyMC-Marketing supports native model restoration. MMM additionally has an MLflow prediction wrapper, but release 1.2.0's built-in point/posterior-prediction route fails on an unsupported original_scale argument. Use the documented native restoration route; do not claim the wrapper is ready for serving. CLV tracking does not supply an equivalent CLV serving wrapper.
• A runs:/ URI addresses a run artifact; a models:/ URI addresses a registered model. Logging or registering either does not deploy a service. Validate the selected prediction method, input schema, scale and runtime dependencies before treating a wrapper as usable for serving.

Avoid workflow contamination

Do not leave pm.sample globally replaced with mock_sample. Mock output is prior-generated infrastructure data, not posterior inference, and may have no sampler statistics. Scope test patches and restore the original callable; see meaningful model testing. Enable autologging once per process, not repeatedly in a notebook loop.

Keep tracking databases, posterior files and raw data out of source control. Artifacts and autologged dataset inputs can contain observed values, predictors and identifying coordinates; use authorized storage and access controls. Do not upload credentials or unapproved data. Diagnose full unthinned chains before making any explicitly labeled reduced-storage artifact.

For model construction and predictions, use pymc-modeling; for convergence, PPCs and LOO interpretation, use arviz-diagnostics. This skill records those workflows; it does not replace them.