luFactor

luFactor(A): object

LU factorization in packed flat storage, for callers that back-substitute many right-hand sides against one factorization on a hot path.

Unlike lu(), this skips building the nested L, U and dense permutation matrix P: it returns the combined LU array directly (unit-diagonal L strictly below the diagonal, U on and above, in row-major n*n storage) together with the permutation vector, so no nested round-trip or permutation-matrix scan is needed. Pair it with luFactorSolve().

Parameters

A

number[][]

Square nested matrix

Returns

object

lu is the combined LU storage (row-major n*n); perm maps factored row k to input row perm[k]; sign is the permutation sign; singular flags a pivot at or below 1e-13 * maxAbs(A).

lu

lu: Float64Array

n

n: number

perm

perm: Int32Array

sign

sign: number

singular

singular: boolean