metric_axioms

std.sets.metric_axioms · Level L3

The axioms of a metric on a finite set, given as its full distance table D, each checked over every pair or triple, as 1 or 0: d(x, y) ≥ 0; d(x, y) = 0 exactly when x = y; d(x, y) = d(y, x); and the triangle inequality d(x, z) ≤ d(x, y) + d(y, z), checked for every y at once as d ≤ the min-plus square of d. A finite metric space is complete: below its smallest positive distance a Cauchy sequence is eventually constant.

d ≥ 0; d(x, y) = 0 ⇔ x = y; d(x, y) = d(y, x); d(x, z) ≤ d(x, y) + d(y, z)

Signature

metric_axioms(D: f64[n, n]) → f64[], f64[], f64[], f64[]

Structure

The function as NOVA stores it: one box per input, operation and output, and arrows that carry values. A double border marks another library function this one runs — called once, or by Scan once per element; select it to open that function.

Df64[n, n]0.0TransposeDtMultiplynilIotaciIotariLessnegEqualiszEqualsymAddcolf1.0AddrowfReduceMaxbad_nEqualeyeReduceMinsymmetricCastcoliCastrowiSubtractnonnegativeEqualsep_okGatherQyzGatherPxyReduceMinseparationAddviaReduceMinshortestGreatertri_badReduceMaxbad_tSubtracttrianglesymmetricf64[]trianglef64[]nonnegativef64[]separationf64[]
  • input
  • operation
  • constant
  • call
  • output

Verification

  • Signature proven by NOVA’s shape solver, for every size.
  • Equal to the reference every pair and triple in exact arithmetic in exact rational arithmetic, on all 40 test cases.
  • All 160 float64 results are exact: the error is zero.
  • Interpreter and NumPy backend return bit-identical results.
  • At float32 too: the 40 test cases rounded to float32, and 40 of them exact, with zero error.
Accuracy in detail
correctly rounded (the float64 nearest the exact value)
100%
bit-equal to the NumPy formula in float64
100%
largest error, in units in the last place
0

Identity

Calls
—
Called by
—
sha256:2a711d5876c8ead0ebf35bc787cfee1aa17233aa06afcda21476af18068edf04

The semantic hash of the graph. It changes when the program changes, and never when only its documentation does.

Control handle

Symbol
Ω:std.sets.metric_axioms · Ω:metric_axioms
Pins
sha256:273f03bc89e4ad0b1dc6b5537a9dab24f01f08f63da9946e13b94725b8750370this graph alone
Evidence
sha256:45ec7921c9d74f05b6e138a32f7c61e675aa22473aa2c2ae0de0893b0178a969the hash of its verification record
Needs
no capability: a pure function

Through NOVA’s control layer, the symbol launches this function only while the program still matches what it pins: a change to this graph, or to any graph it reaches, needs a migration first.

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