# File numerics/src/tools/quartic.h¶

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quartic algorithm to find roots of quartic polynomials

Functions

int BIQUADROOTS(double p[5], double r[3][5])
int CUBICROOTS(double p[5], double r[3][5])
int QUADROOTS(double p[5], double r[3][5])

CACM Algorithm 326 Roots of low order polynomials Author: Terence R.F.Nonweiler CACM (Apr 1968) p269 Translated into c and programmed by M.Dow ANUSF, Australian National University, Canberra, Australia m.dow@anu.edu.au.

Suite of procedures for finding the (complex) roots of the quadratic, cubic or quartic polynomials by explicit algebraic methods. Each Returns x=r[1][k] + i r[2][k] k=1,…,n, where n={2,3,4} as roots of sum_{k=0:n} p[k] x^(n-k) =0 Assume p[0]<>0 (overflows otherwise) Suite of procedures for finding the (complex) roots of the quadratic,

Return
always 0
Parameters
• p: Coefficients of the polynomial
• r: root of the polynomial r[1][k] real part of the kth root r[2][k] imaginary part.