---
title: "school-student-vidtvorant-runner — Mova code model"
description: "Mova code model of tools/approx/examples/student_vidtvorant.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/tools/approx/examples/student_vidtvorant.rs.groupant/"
---
Elamur: [Mova](https://md.mova.elamur.ai/free/en/) · [Dictionary](https://md.dictionary.elamur.ai/free/en/) · [Research](https://md.research.elamur.ai/free/en/) · **Groupants**

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# school-student-vidtvorant-runner

The groupant beside tools/approx/examples/student_vidtvorant.rs in the Mova repository: what the code computes, what it never does, how to go back from its outputs, its invariants, cost and checks.

## Facts

- **kind:** groupant
- **status:** partial source derived instance
- **source:** [`tools/approx/examples/student_vidtvorant.rs`](https://github.com/ElamurAI/mova-free/blob/main/tools/approx/examples/student_vidtvorant.rs)
- **source SHA-256:** `7a954e6d9e7d006c…`
- **repository folder:** [`tools/approx/examples/student_vidtvorant.rs.groupant`](https://github.com/ElamurAI/mova-free/tree/main/tools/approx/examples/student_vidtvorant.rs.groupant)
- **repository commit:** `48f2e6f74146`

> **Implementation material.** A Mova code model describes this code at one source revision: partial models, finite checks and their stated scope. It is not a reviewed general exposition, and its labels are shown as written, never raised.

## Components

| component | label | where |
|---|---|---|
| **approximant** | source derived | [forward](#forward) |
| **ast** | partial | `syntax.json` |
| **cost** | measured 2026 11 04 | [cost](#cost) |
| **descriptant** | present | [epoch-memory](#epoch-memory) |
| **invariant** | source derived | [invariant](#invariant) |
| **tests** | executed bounded checks | [tests](#tests) |

## Obernants

The typed relations around the forward model: the behaviour complement (what the code never does), the reverse reconstruction (every input compatible with an output) and specialised views.

| id | type | label | where |
|---|---|---|---|
| `school-student-vidtvorant-runner-behavior-complement` | behavior_complement | partial source derived model | [behavior-complement](#behavior-complement) |
| `school-student-vidtvorant-runner-reverse-reconstruction` | reverse_reconstruction | partial source derived model | [reverse-reconstruction](#reverse-reconstruction) |

## Model text


`student_vidtvorant SCHOOL_DIR PROBE_ROOT OUT_DIR COURSE...`: fits and measures the student's vidtvorant
([world/src/knowledge.rs.groupant/student-vidtvorant.groupant](https://md.groupants.elamur.ai/free/en/mova/world/src/knowledge.rs.groupant/student-vidtvorant.groupant/))
against `student_probe` traces.

### forward

Load each course's traces from every repetition directory; refuse a course whose choices or understanding differ
between repetitions; take each question's median answer time. Read the lesson files' teaching lines. Parity folds
(fit on even lessons, test odd; the reverse): grid (anchor_min, own_min) ∈ {2,3}², perceptron five epochs, gap gate
then no-gap gate from twenty score quantiles, best training agreement. Predict every question out of fold; fit the
time model per fold on the other fold's questions. Report agreement (choice, understood, correctness), per-course
scores, disagreement classes by the student's route (guess, support, support tie, rule or count) with examples, and
a course split (fit on courses 1, 3, 5…, test the others). Then time `predict` per question with the first fold's
parameters.

### invariant

`semantic.json` depends only on the traces' choices, scores and median times and on the lesson files: two runs are
byte-identical (checked four times, 2026-11-04). `timing.json` holds the nondeterministic own-speed numbers apart,
together with the deterministic time-model errors. No held-out set is read: the school's tests and exams are the
pupil's diagnostic score, and folds are by lesson parity or by course.

### cost

≈ 4 × (5 epochs + 40 gate replays) replays per fold, three folds; ≈ 170 s on one core for ten courses (7 412
questions).

### behavior-complement

Does not run the student, the parser or any teacher; does not write outside OUT_DIR; does not register or claim a
cap; does not select courses after seeing results (the course list is the command line).

### reverse-reconstruction

A report is compatible with every set of traces giving the same per-question choices, scores and median times; the
examples listed are a deterministic subset, not all disagreements.

### tests

The included vidtvorant's six unit tests run with `cargo test --release -p mova-approx --example
student_vidtvorant`; the repetition-consistency refusal and the semantic determinism are exercised by every run.

### epoch-memory

2026-11-04: first version; results in `$MOVA_DATA/runs/mova-speed-2026-11-04/vid-a..d`.