source: trunk/source/global/HEPNumerics/include/G4AnalyticalPolSolver.hh @ 1202

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// $Id: G4AnalyticalPolSolver.hh,v 1.5 2006/06/29 18:59:23 gunter Exp $
// GEANT4 tag $Name: geant4-09-02-ref-02 $
//
// Class description:
//
// G4AnalyticalPolSolver allows the user to solve analytically a polynomial
// equation up to the 4th order. This is used by CSG solid tracking functions
// like G4Torus.
//
// The algorithm has been adapted from the 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
// Assumes p[0] != 0. (< or > 0) (overflows otherwise)

// --------------------------- HISTORY --------------------------------------
//
// 13.05.05 V.Grichine ( Vladimir.Grichine@cern.ch )
//          First implementation in C++

#ifndef G4AN_POL_SOLVER_HH
#define G4AN_POL_SOLVER_HH

#include  "G4Types.hh"

class G4AnalyticalPolSolver 
{
  public:  // with description

    G4AnalyticalPolSolver();
    ~G4AnalyticalPolSolver();

    G4int QuadRoots(    G4double p[5], G4double r[3][5]);
    G4int CubicRoots(   G4double p[5], G4double r[3][5]);
    G4int BiquadRoots(  G4double p[5], G4double r[3][5]);
    G4int QuarticRoots( G4double p[5], G4double r[3][5]);
};

#endif