Lagrange interpolation polynomial

E156183

The Lagrange interpolation polynomial is a classical formula in numerical analysis that constructs a unique polynomial passing through a given set of data points, widely used for interpolation and approximation.

All labels observed (2)

How this entity was disambiguated

Statements (48)

Predicate Object
instanceOf interpolation method
mathematical formula
numerical analysis concept
polynomial
advantage does not require solving linear systems for interpolation
explicit closed-form expression
appliesTo complex-valued functions
functions defined on intervals or discrete sets
real-valued functions
assumes interpolation nodes are pairwise distinct
basisDefinition L_j(x) = Π_{m≠j} (x - x_m)/(x_j - x_m)
component Lagrange basis polynomial
degree at most n if there are n+1 data points
disadvantage computationally expensive to update when adding new nodes
numerically unstable for high-degree interpolation on equidistant nodes
errorTerm E(x) = f^{(n+1)}(ξ)/(n+1)! Π_{j=0}^n (x - x_j)
involves (n+1)th derivative of the interpolated function
field approximation theory
numerical analysis
polynomial interpolation
formula P(x) = Σ_{j=0}^n y_j L_j(x)
generalizationOf linear interpolation
quadratic interpolation
input function values at interpolation nodes
set of interpolation nodes
namedAfter Joseph-Louis Lagrange
notation often denoted by P_n(x) or L_n(x)
origin 18th century
output polynomial function
property uniqueness of interpolating polynomial for distinct nodes
purpose construct a polynomial passing through given points
interpolate a function from discrete data points
relatedTo Newton interpolation polynomial
Runge phenomenon
Vandermonde matrix
barycentric interpolation formula
representation linear combination of Lagrange basis polynomials
requires arithmetic operations on field elements
satisfies P(x_j) = y_j for all interpolation nodes x_j
stability improved by barycentric form
usedFor curve fitting through exact data points
function approximation
numerical differentiation
numerical integration (via interpolatory quadrature)
usedIn computer graphics
data fitting
finite element method shape function construction
signal processing

How these facts were elicited

Referenced by (2)

Full triples — surface form annotated when it differs from this entity's canonical label.

Joseph-Louis Lagrange knownFor Lagrange interpolation polynomial
Shamir secret sharing scheme basedOn Lagrange interpolation polynomial
this entity surface form: Lagrange interpolation