[lean-squad] feat(fv): BlockStats Lean implementation + computeMaxSpeedFromDistance informal spec#134
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dsyme merged 1 commit intoMay 19, 2026
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…e informal spec
Task 2: informal spec for math::trajectory::computeMaxSpeedFromDistance (target 56).
- specs/computemaxspeed_informal.md: full pre/postconditions, kinematic
derivation of the quadratic formula, discriminant non-negativity, edge cases,
examples, and Lean modelling plan.
Task 4: Lean implementation and proofs for BlockStats<Type,M> (target 57).
- lean/FVSquad/BlockStats.lean: scalar Int model of the running-sum accumulator.
- 10 theorems, 0 sorry, lake build PASSED.
Theorems proved:
bsUpdate_count, bsUpdate_sum, bsUpdate_sumSq, bsUpdate_sumSq_nonneg,
bsUpdate_mono_count, bsReset_zero, bsFold_count, bsFold_sum,
bsFold_sumSq_nonneg, bsMean_single.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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🔬 Lean Squad — automated formal verification, run 137.
Summary
This PR completes two tasks:
Task 2 (Informal Spec):
computeMaxSpeedFromDistanceinformal specificationTask 4 (Implementation Extraction):
BlockStatsLean implementation model + 10 proved theoremsTask 2:
computeMaxSpeedFromDistanceInformal Spec (target 56)File:
formal-verification/specs/computemaxspeed_informal.mdDocuments the kinematic quadratic formula used by PX4's velocity smoother to compute the maximum initial approach speed for a braking manoeuvre:
b = 4a2/j,c = -2ad - vf2,result = max(0.5(-b + √(b2-4c)), vf)b2 - 4c ≥ 0whena, d ≥ 0)accel=0,dist=0, large distance), worked examplesReal.sqrtfrom MathlibTask 4:
BlockStatsLean Implementation + Proofs (target 57)File:
formal-verification/lean/FVSquad/BlockStats.leanScalar
Intmodel ofcontrol::BlockStats<Type,M>— the running-sum/sum-of-squares/count accumulator. Proves the fundamental correctness invariants:Theorems Proved (10, 0 sorry)
bsUpdate_countbsUpdate_sumuto running sumbsUpdate_sumSqu2to sum-of-squaresbsUpdate_sumSq_nonnegbsUpdate_mono_countbsReset_zerobsFold_countbsFold_sumbsFold_sumSq_nonnegbsMean_singleApproximations
The model specialises to
M=1(scalar) withIntarithmetic. Floating-point rounding, theBlockclass hierarchy, and dimension-genericVector<Type,M>operations are abstracted away.Verification Status
Files Changed
formal-verification/specs/computemaxspeed_informal.md— new informal spec (target 56 → phase 2)formal-verification/lean/FVSquad/BlockStats.lean— new Lean file (target 57 → phase 5)formal-verification/lean/FVSquad.lean— added import for BlockStats