Train on the catalog cartpole
Every simulo create starter targets the same immutable global-catalog
version, simulo/robot/cartpole:v1. This guide runs the training
template end to end and explains what each part of the
output means.
Scaffold and run
Section titled “Scaffold and run”simulo create cartpole_demo --type trainingcd cartpole_demosimulo run app.py --num-envs 4096 --max-iterations 200--num-envs and --max-iterations are this app’s own flags — the
entrypoint’s default values, forwarded through simulo run. Raise
--max-iterations for a longer, better-converged run; lower --num-envs
for a faster, noisier one.
The log lines and result fields below are what a real run produces; the reward numbers are an illustrative example, not a measured benchmark — every training run lands somewhere different.
Following job <job-id> (--detach to submit without waiting)...[train] iteration 1/200 ...[train] Best checkpoint saved at iteration 150 (reward=289.42)[train] iteration 200/200 ...simulo result{ "checkpoint": "/out/cartpole_demo_final.pt", "num_envs": 4096, "best_reward": 294.65, "iterations": 200 }Reading the task
Section titled “Reading the task”The scaffolded CartpoleDemoTask (in app.py) is worth reading end to end —
it’s the shape every task follows, regardless of robot:
- Observation (4-dim): pole angle, pole angular velocity, cart position, cart velocity.
- Action (1-dim): a scaled horizontal force applied to the cart.
- Reward: a weighted sum of “stayed alive”, a termination penalty, and
penalties on pole angle, cart velocity, and pole velocity — the classic
cartpole shaping, tunable via the
rew_scale_*class attributes. - Termination: the cart leaving its track, or the pole falling past ±90°.
Best vs. latest
Section titled “Best vs. latest”Training keeps two checkpoints: latest.pt (for resuming) and best.pt
(the highest-reward policy seen so far, with a best.json sidecar recording
when it was captured). The best checkpoint is often captured mid-run, not at
the final iteration — a last-checkpoint-only workflow would lose it.
simulo modelsNAME KIND SIZE SHA256 CREATED MODEL IDlatest.pt latest 2148728 b7e410c92a55 2026-07-10T18:05:02Z 51aa...best.pt best 2148728 3f9c2ab81d04 2026-07-10T18:04:18Z 8c2f...Full detail on downloading these: Retrieve and verify models.
- Publish and pin your own robot in place of the catalog cartpole: Bring your own robot.
- Keep training the policy you just trained: Continue training.
- Watch the next run live in your browser: Watch a run live.