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asingh15/prm-sft-polaris-mc

PRM-SFT Polaris MC — Monte-Carlo value (unfiltered) Soft-target process reward model (PRM) training data with per-prefix Monte-Carlo values, in the style of Math-Shepherd. Each row is one prefix of a reasoning trace on a Polaris math problem, labeled with V(prefix)=P(correct∣prefix)=#correct continuations#continuationsV(\text{prefix}) = P(\text{correct} \mid \text{prefix}) = \frac{\#\text{correct… See the full description on the dataset page: https://huggingface.co/datasets/asingh15/prm-sft-polaris-mc.

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PRM-SFT Polaris MC — Monte-Carlo value (unfiltered)

Soft-target process reward model (PRM) training data with per-prefix Monte-Carlo values, in the style of Math-Shepherd. Each row is one prefix of a reasoning trace on a Polaris math problem, labeled with

$$V(\text{prefix}) = P(\text{correct} \mid \text{prefix}) = \frac{\#\text{correct continuations}}{\#\text{continuations}}$$

estimated from N shared-prefix continuations sampled by Qwen3.5-4B.

This is the unfiltered set: every prefix is kept, including the fully-collapsed V=0 and V=1 prefixes. It is not filtered to mid-difficulty problems or to the uncertain V∈[0.1,0.9] band.

Splits

splitrowsnotes
train126,987
validation2,471128 problems held out by problem id

Value distribution (train)

bucketfraction
V == 016.6%
V == 153.9%
0 < V < 129.4%
V ∈ [0.1, 0.9]17.4%
correct (V ≥ 0.5)75.5%

Mean V = 0.737. The mass at 0/1 reflects label collapse on problems the base model reliably solves or reliably fails — the reason value-filtered variants exist.

Columns

columntypemeaning
messageslist[dict]chat turns: a user judge prompt (question + prefix) and a placeholder assistant "yes" verdict token
rewardfloatthe Monte-Carlo value V — the training target
correctboolV ≥ 0.5
labelstrplaceholder verdict string ("yes")
idstrproblem id (splits are disjoint by this)
sourcestr"polaris"
sample_indexintbase-trace index the prefix came from
step_idxintprefix position within the base trace
num_stepsintnumber of steps in the base trace
loss_weightfloat1.0 (unused; superseded by soft-target reward)
enable_thinkingboolfalse

Intended training use

One row per prefix with a placeholder yes verdict token. The soft-target PRM loss reads reward as V and minimizes soft cross-entropy at the verdict position,

$$-\big[\,V \log P(\text{yes}) + (1-V)\log P(\text{no})\,\big],$$

so P(yes) regresses to V. Same schema as the outcome-PRM sets, so it is concatenable.

Provenance

Branched-rollout pipeline: build branch set (prefixes) → sample N shared-prefix continuations → grade (math_verify + LLM-judge relabel) → aggregate to per-prefix V. Correctness comes from the relabeled grades (the raw branch shard is largely ungraded).