Status: POC. 100-epoch reproduction (paper uses 800). Linear-probe
val_acc 23.77% (47× chance on 200 classes). Random-encoder baseline
computed 2026-05-16: random ViT-S + frozen + linear probe + matched
100 epochs reaches val_acc 8.50% (17× chance). JEPA training contributes
2.80× over random encoder, adding 15.27pp absolute.
Final metrics (epoch 99)
Metric
Value
SIGReg loss
1.584 (down from 11.826 at epoch 0)
Invariance loss
0.126 (down from 0.447)
Probe CE loss
3.610 (down from 5.195)
Linear-probe val_acc
0.2377
No representation collapse — SIGReg loss converges, val_acc rises monotonically.
Baseline comparison
Setup
val_acc
× chance
Δ over chance
Chance (uniform)
0.005
1.0×
—
Random ViT-S + frozen + LP
0.0850
17.0×
+0.080
LeJEPA-trained ViT-S + frozen + LP
0.2377
47.5×
+0.233
Δ (JEPA over random)
+0.1527
2.80×
—
Honest framing: JEPA training adds 15.27pp absolute over a matched-architecture
random encoder. About 36% of the val_acc-over-chance gain comes from "random
high-dim projection + linear probe is non-trivial on Tiny-ImageNet" (a known
random-features effect, Rahimi & Recht 2007), 64% comes from JEPA training.