Troubleshoot scenarios and solves

Start from the state GroupMixer reports

Different states need different responses:

Do not respond to every problem by increasing runtime. Runtime cannot repair invalid references, insufficient capacity, or contradictory requirements.

Scenario needs changes

GroupMixer performs deterministic checks before starting the worker. Current preflight checks include:

• blank or duplicate person IDs;
• blank or duplicate group IDs;
• constraints that reference people or groups that no longer exist;
• insufficient total group capacity for the people attending each session.

The message shows the first issue and may report additional issue count. Correct the named problem, then run again.

Insufficient capacity

Open Groups and inspect the reported session. Increase real capacity, add a real group, or correct attendance. Do not inflate capacity merely to make validation pass if the room cannot hold that assignment.

Invalid reference

A person, group, or attribute may have been deleted or replaced after a constraint was created. Reopen the named constraint and select current entities, or remove the obsolete constraint.

Conflicting requirements

Examples include too many fixed people for one group, a fixed placement incompatible with a together rule, or the same people required together and apart in the same scope.

Requirements are invariants. Resolve the contradiction by correcting the underlying event policy or its scope. Do not simply convert a real requirement into a preference to force a result.

Backend feasibility diagnostics may identify capacity, group-bound, reference, fixed-placement, together/apart, or unsatisfied-core evidence beyond the browser preflight.

Weighted deviations are not solve failures

A result can be valid while Repeat Encounter, Attribute Balance, Attribute Sum, Encounters, Group Visits, or another weighted preference has a nonzero deviation.

Open the relevant compliance card and ask:

1. Which people, groups, and sessions were measured?
2. What actual value and bound produced the raw deviation?
3. Was the target mathematically feasible with attendance and capacity?
4. Which other preferences or objectives competed with it?
5. Would changing the scope, weight, or curve express the real priority more accurately?

Do not report a weighted miss as a required-rule violation. Conversely, do not dismiss an Immovable People, Must Stay Together, or Must Stay Apart violation as an acceptable trade-off.

Warm start could not be used

A warm-start result can become incompatible after scenario changes. GroupMixer clears a failed warm start and asks you to run without it or choose a newer compatible result. A Warm Start Adjusted warning means reconciliation preserved some assignments and repaired, filled, or dropped others; review the counts before trusting continuity.

Worker or WebAssembly could not start

For worker initialization, progress-mailbox, or WebAssembly loading failures:

1. Reload the page once.
2. Confirm you are using a current Chrome, Edge, Firefox, or Safari browser.
3. Disable script-blocking extensions or network filters for GroupMixer.
4. Use the normal GroupMixer site rather than a restricted embedded environment.
5. Retry with fewer Parallel Auto lanes if memory pressure is plausible.

If the same runtime failure continues, open Advanced error details and use Report issue when available. Copy the error text manually if browser clipboard permission prevents the Copy action from confirming success.

Solver budget ended or infeasibility was reported

A fixed runtime is also a normal optimization budget. If the run returns a valid result when that budget ends, solving completed with the best incumbent found within the allotted time; review its quality evidence normally. If construction or feasibility search times out without a valid result, feasibility was not established within the budget.

Increase effort only after checking requirements, group capacities, and scope. Simplifying an accidental rule can be more useful than a longer run; removing a genuine requirement is not an acceptable diagnostic shortcut.

A structured infeasibility diagnosis should name the conflict category and route you toward the relevant editor. If the same unexplained infeasible state occurs repeatedly, the error dialog offers escalation for a bug report.

Cancellation and best-so-far

Cancel asks whether to discard progress or save it. Saving requires a valid best-so-far snapshot. If no snapshot exists, assignments are empty, evaluation fails, or persistence fails, GroupMixer reports that nothing was saved and leaves cancellation unresolved until you choose another action.

Ordinary user cancellation is not submitted as a solver failure report.

Result or workspace is missing

Result not found means the saved result ID could not be loaded for the current scenario. Return to Results History and choose an available result. Saved result routes depend on browser persistence; they are not universal public URLs.

If a result opens without usable scenario context, return to Results History or reload the workspace before rerunning. A saved result snapshot normally preserves the scenario used for that run.

Workspace errors use specific titles such as Unable to load workspace, Unable to migrate saved setup, Unable to create workspace, or Unable to save this example. Reload once and check browser privacy or storage restrictions. Do not clear browser storage before exporting anything you can still access.

Report an unexpected solver result

Report the issue when:

• a returned schedule violates Immovable People, Must Stay Together, or Must Stay Apart;
• a person is assigned twice in one session or outside attendance;
• a group exceeds its enforced capacity;
• the runtime repeatedly fails with an unknown or unreachable error;
• the displayed result and its saved scenario snapshot disagree.

Include the visible summary and Advanced error details. GroupMixer may automatically send a bounded failure report to configured telemetry services with participant names, group labels, attribute names, and attribute values replaced by technical placeholders. Reproducible structure such as counts, attendance shape, capacities, constraints, settings provenance, and diagnostics can remain. Reporting is best-effort and offline reports are not queued. Never paste participant names or sensitive scenario data into a public report unless you intend to disclose them.