Detecting and resolving conflicts (at generation time)

Omniscol detects conflicts continuously during the preparation of a timetable and at every manual placement. The diagnostic distinguishes blocking conflicts from unmet constraints and from warnings that call for a decision, and it encodes this severity with a color — on the candidate slots and the selection lists when you place a lesson, and on each row of the diagnostic panel. Automatic generation is a separate computation (the solver places under constraints, or leaves a lesson unplaced): its diagnostic is covered in Diagnosing a failed generation.

What the diagnostic checks

• Occupancy (double-booking) — a teacher, a class, a group, a student, a classroom or a resource cannot serve two overlapping lessons, unless explicitly modeled (compatible groups, divisions, large rooms).
• Availability and time constraints — a period declared unavailable, or an unmet time constraint (teacher, class, group, classroom, subject, site), graded by the priority of the constraint. An imposed date window, however, is always blocking.
• Capacity and service — a classroom over capacity, a resource requested in more units than available, an unsuitable classroom (capacity, specialization, site), or a teacher's service hours exceeded.
• Grid overflow — the lesson hours to place exceed, or approach, the number of open slots in the grid, for a teacher or for a whole class.
• Locations and travel — insufficient travel time between two sites for a teacher or a class, or two subjects declared incompatible placed at the same time.
• Calendar — a lesson placed on an absence (teacher or class), a closed day / holidays, or an incompatible event.
• Modeling — a broken alignment (aligned groups without a shared lesson), a different number of lessons between groups of the same division or the same alignment, a missing teacher or classroom, or an incomplete configuration (site, grid, a setting required before generation).

Severity levels

The same severity scale — green, yellow, orange, red — colors several places of the editing screens.

On the candidate slots, when you position a lesson (see Manual placement). And on each option of the selection lists: when you choose a teacher, a classroom, a resource, a group or participants for a lesson, each entry carries a calendar icon colored by its level at the target slot — green if the entity is free, red if it is busy — with the details on hover. Only a red unavailability (busy, closed period) prevents the choice; a classroom that is too small or wrongly specialized remains selectable, with a warning.

In the diagnostic panel. Each listed problem carries a level, reused by the filter. The panel groups orange and yellow under a single “important” level, and adds an “advice” level for non-blocking information:

When the Block conflicting choices (hard constraints) option is active, Omniscol prevents choices that would create a strong constraint; otherwise, the alert stays visible so the administrator can decide.

Grid overflow and pressure

Omniscol permanently compares the lesson hours to place with the number of open slots in the grid — for each teacher (per class and per site) and for each whole class. The message shows both values, for example “18 h / 16 h”. Three thresholds, depending on the fill level:

This computation only runs if at least one site is configured, and reports nothing as long as the grid stays under 90%. It measures the required hours against the available slots — not to be confused with a teacher's service hours overrun (taught hours against contractual hours), which shares the same colors but remains a separate detection.

All detections

Navigating from an alert

Each row of the panel is clickable: the magnifier leads directly to the lesson, group or class concerned — the fastest way to isolate the context of a conflict. For a group conflict (division, alignment), the icon keeps only the related groups, which makes the constraint stand out when the raw diagnostic is not enough.

Resolving a conflict

The most frequent fixes are:

• moving a lesson;
• changing the teacher, classroom or resource;
• adjusting a constraint that is too strong;
• correcting an unavailability or an absence entered by mistake;
• creating or fixing the groups, divisions or alignments;
• adding a compatible classroom, a capacity or a specialization;
• locking a lesson that must stay fixed before rerunning a generation.

If generation does not find a complete solution, it can return a partial timetable: the unplaced lessons remain in the sticky notes bar of lessons to place. Fix the priority diagnostics, then rerun or manually position the remaining cases.

Cases that call for a decision

Some signals correspond to a management decision rather than a data-entry error. Examples:

• an exam with a main room and an extra-time room;
• a capacity declared above the seats entered when the institution knows that some of the enrolled will not be present;
• an annex room not modeled in Omniscol.

In these cases, it is better to model the situation explicitly when possible: multiple rooms, adapted groups, a corrected capacity or a separate event. Leaving a deliberate alert must remain a decision known to the team, not permanent noise.