arc2/README.md

FPRM — ARC-2-concept (single-z, conv1d)

Fixed-Point Tiny Recursive Model (FPRM / FPTRM single-z) trained on ARC-2-concept (arc2concept-aug-1000, the 1000-task augmented build). Evaluated with two attempts it reaches 6.2% pass@2 — ARC-2-concept is substantially harder than ARC-1-concept under the same recipe.

Original run name: fptrm_singlez_arc2_lr1e-3_wd0.01_det_a0.75_0.25_iter8 (step_723914 = final; resumed run).

Results

metric	value
test pass@2	6.2%
eval budget	max_iter_eval=1000 (stepsize_decay 0.9, patience 5)
checkpoint	step_723914 (final, EMA)

Architecture

	value
model	FPTRM single-z (fp_trm_singlez)
hidden size / heads / expansion	512 / 8 / 4
H-cycles / L-cycles	0 / 0
H-layers / L-layers	0 / 2
n_backwards_L	6
positional enc / puzzle-emb len	RoPE / 16
halting	fixed-point + Q-head (ACT)
max_iter (train)	8 (deterministic)
max_iter (eval)	1000
stepsize-decay / patience	0.9 / 5
fp_thresh	0.1
norm type / placement	pre-norm / none
residual scaling	input-independent (α₁, α₂ init = 0.75, 0.25)
conv branch	conv1d (kernel 4)
loss	stablemax cross-entropy, deep supervision, q_loss_coeff 0.5

Optimizer

	value
optimizer	adam_atan2 (β = 0.9, 0.95)
learning rate	1e-3 (constant, no warm-up)
weight decay	0.01
puzzle-emb LR	1e-2 (decoupled)
puzzle-emb WD	1.0
batch size	768
epochs	100000
EMA	enabled (rate 0.999)
seed	0

Files

• step_<N> — EMA-averaged eval checkpoints (~1.7 GB each), N = 72391 … 723914 (final). Because ema=True, step_<N> is the EMA copy — these are the weights to load for inference/eval.
• all_config.yaml — the exact training configuration.
• fp_trm_singlez.py, losses.py — model and loss source for this checkpoint.
• evaluator_ARC_step_0/submission.json — ARC evaluation submission (predictions) for this run.

Reproduce the 6.2%

1. Train with all_config.yaml (FPTRM single-z, conv1d/k4, pre-norm / placement none, input-independent residual scaling, adam_atan2, lr 1e-3, decoupled puzzle-emb LR 1e-2, 100000 epochs) on the arc2concept-aug-1000 build. Produces step_723914.
2. Eval at max_iter=1000 on the final EMA checkpoint and report pass@2 (two attempts).