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get-implicit-form1-error-counters

function getImplicitForm1ErrorCounters(ps: number[][]): object

Defined in implicit-form/get-error-counters/get-implicit-form1-error-counters.ts:45

Returns a representation of the error (from which an absolute error bound can be calculated) when calculating the implicit form of the given bezier curve (using getImplicitForm1 or getImplicitForm1Dd).

  • returned coefficients are subscripted to match their monomial's variables, e.g. vₓᵧ is the coefficient of the monomial vₓᵧxy
  • the implicit form is given by: vₓx + vᵧy + v
  • The returned error representation needs to be multiplied with Stewart error counters¹ and an appropriate error function, γ, depending on the precision used (e.g. double or double-double). This is explained in more detail below. See also Higham 2002 p. 68 near the bottom.

(1) G. W. Stewart. Introduction to Matrix Computations. Academic Press, New York, 1973. xiii+441 pp. ISBN 0-12-670350-7

The absolute erros below can be calculated as follows (where <E> are the error counters as indicated in the comments of the return value below):

  • double precision: <E> * (γ(1)) * result_
  • double-double precision: <E> * (2*γγ(3)) * result_

where [[γ]] and [[γγ]] are the usual error functions (provided in this library as functions with the same name) with γ(1) === 1.1102230246251568e-16 and γγ(3) === 3.697785493223493e-32.

return {
vₓ_, // <1>
vᵧ_, // <1>
v_ // <3>
}

Parameters:

NameTypeDescription
psnumber[][]

Returns: object

NameType
vₓ_number
vᵧ_number
v_number