leading_minors

std.linalg.leading_minors · Level L4

The leading principal minors Δ₁, …, Δₙ of an integer matrix (the determinants of its top-left k × k blocks), exactly, by fraction-free elimination without row exchanges: a Scan of minor_step. Each Δ_k is right as long as the earlier ones are nonzero; valid marks those, and after the first zero minor the later values are not minors.

Δ_k = det A[1..k, 1..k]

Signature

leading_minors(A: f64[n, n]) → f64[n], f64[n]

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.

Af64[n, n]0.0ReduceSumrows1.0Multiplym0IotaksScan·minor_stepMs, Ps, NsSlicelastReduceSumminorsEqualnzSubtractokCumMinvalidvalidf64[n]minorsf64[n]
  • input
  • operation
  • constant
  • call
  • output

Verification

  • Signature proven by NOVA’s shape solver, for every size.
  • Equal to the reference the same elimination on Python integers in exact rational arithmetic, on all 40 test cases.
  • All 300 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 inside the running error bound at u = 2⁻²⁴; the closest uses 1% of it.
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

sha256:e4a8cc1dcae9fcfe6975e12dabd123748fd369aa8fe7504d11698da5cdfe384d

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

Control handle

Symbol
Ω:std.linalg.leading_minors · Ω:leading_minors
Pins
sha256:df8c8fa628126061cc75cd3e9389ca26e701e17b448f6242ead597da956824f3this graph and the 1 it reaches through calls
Evidence
sha256:c0024bb3d5f7b5f17ae4a01eae426b3c86955a07746eff984e18eeda2142ba11the 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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