# durand-kerner

Finds multiple roots of polynomials using Weierstrass' method

``npm install durand-kerner``

# durand-kerner

Finds all the roots of a polynomial by Weierstrass' method (or known in Abramowitz&Stegun as the Durand-Kerner method). This is basically a generalization of Newton's method that works for multiple roots.

# Use

Install using npm:

``````npm install durand-kerner
``````
``````var findRoots = require("durand-kerner")

var roots = findRoots([1, 1, -1])  // Finds roots for 1 + 1*x - 1*x^2

// Now:
//      roots[0] = real part of roots
//      roots[1] = imaginary part of roots

for(var i=0; i<roots.length; ++i) {
console.log(roots[0][i] + "+" + roots[1][i] + "i")
}

// Prints:
//  1.618033988749895+0i
//  -0.6180339887498949+0i
``````

## `require("durand-kerner")(r_coeff[, i_coeff, n_iters, tolerance, initial])`

Finds the roots of a polynomial whose real coefficients are given by `r_coeff` and imaginary coefficients by `i_coeff`.

• `r_coeff` - the real part of the polynomial's coefficients, stored in an array
• `i_coeff` - the imaginary part of the polynomial's coefficients (default all 0)
• `n_iters` - Maximum number of iterations to run before bailout. Default is `100 * n * n`
• `tolerance` - Stopping threshold. Default is `1e-6`
• `initial` - Initial guess for solution vector. This also gets the solution (optional)

Note if initial `< r_coeff.length-1`, then

Returns An array of roots.

# Credits

(c) 2013 Mikola Lysenko. MIT License

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