horner

horner

Evaluates polynomials using Horner's rule.

Example

Real polynomial

Evaluate the polynomial 1 + 2 * x^2 at x = 2:

var horner = require("horner")

console.log(horner([1, 0, 2], 2.0))

Output

9

Complex polynomial

Evaluate the polynomial 2 - 3i * x + (4 + 5i)*x^2 at x = 1+2i:

var horner = require("horner")

console.log(horner([[2, 0, 4]     //Real coefficients
                  , [0, -3, 5]]   //Imaginary coefficients
                  , [1, 2]))

Output

[-24,-2]

Install

Install using npm:

npm install horner

API

require("horner")(poly, z)

Evaluates the polynomial at the point z

• poly is the coefficients of the polynomial arranged in increasing degree. If complex, is a pair of arrays, the first representing the real coefficients and the second representing the imaginary coefficients.
• z is the point to evaluate the polynomial at. Either a scalar for a real valued function or a pair for a complex number.

Returns: A scalar for real results, a pair for complex results

Time Complexity: O(poly.length)

License

(c) 2013 Mikola Lysenko. MIT License