ndarray-function-basis

ndarray-function-basis

Construct an ndarray basis given a sequence of points and functions

Introduction

This module extends the idea of a Vandermonde matrix to a sequence of arbitrary functions. It constructs a set of basis vectors that can be used in a least squares curve fit.

Usage

basis( x, functions [, dtype])

• x: a vector of numbers for the independent variable at which the functions are evaluated
• functions: an Array of functions that take a Number as input and return a Number as output
• dtype (optional): the datatype of the output array, as listed in the ndarray documentation.

Example

For example, to construct a sinusoidal basis with period 2*pi and a constant offset,

var basis = require('ndarray-function-basis'),
    ndarray = require('ndarray');

var x = ndarray([1,2,3,4]);

var f1 = function(x) { return 1; }
var f3 = Math.sin;
var f4 = Math.cos;

var y = basis(x, [f1, f2, f3]);

See also:

ndarray-householder-qr: Householder QR for least squares curve-fitting ndarray-vandermonde: Construct a Vandermonde (polynomial) basis

Credits

(c) 2015 Ricky Reusser. MIT License