include/Geant4/G4JTPolynomialSolver.hh

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0025 //
0026 // G4JTPolynomialSolver
0027 //
0028 // Class description:
0029 //
0030 // G4JTPolynomialSolver implements the Jenkins-Traub algorithm
0031 // for real polynomial root finding.
0032 // The solver returns -1, if the leading coefficient is zero,
0033 // the number of roots found, otherwise.
0034 //
0035 // ----------------------------- INPUT --------------------------------
0036 //
0037 //    op     - double precision vector of coefficients in order of
0038 //             decreasing powers
0039 //    degree - integer degree of polynomial
0040 //
0041 // ----------------------------- OUTPUT -------------------------------
0042 //
0043 //    zeror,zeroi - double precision vectors of the
0044 //                  real and imaginary parts of the zeros
0045 //
0046 // ---------------------------- EXAMPLE -------------------------------
0047 //
0048 //    G4JTPolynomialSolver trapEq ;
0049 //    G4double coef[8] ;
0050 //    G4double zr[7] , zi[7] ;
0051 //    G4int num = trapEq.FindRoots(coef,7,zr,zi);
0052 //
0053 // Translated from original TOMS493 Fortran77 routine (ANSI C, by C.Bond).
0054
0055 // Author: Oliver Link, 15.02.2005
0056 //         Translated to C++ and adapted to use STL vectors.
0057 // --------------------------------------------------------------------
0058 #ifndef G4JTPOLYNOMIALSOLVER_HH
0059 #define G4JTPOLYNOMIALSOLVER_HH 1
0060
0061 #include <cmath>
0062 #include <vector>
0063
0064 #include "globals.hh"
0065
0066 class G4JTPolynomialSolver
0067 {
0068  public:
0069   G4JTPolynomialSolver() = default;
0070   ~G4JTPolynomialSolver() = default;
0071
0072   G4int FindRoots(G4double* op, G4int degree, G4double* zeror, G4double* zeroi);
0073
0074  private:
0075   void Quadratic(G4double a, G4double b1, G4double c, G4double* sr,
0076                  G4double* si, G4double* lr, G4double* li);
0077   void ComputeFixedShiftPolynomial(G4int l2, G4int* nz);
0078   void QuadraticPolynomialIteration(G4double* uu, G4double* vv, G4int* nz);
0079   void RealPolynomialIteration(G4double* sss, G4int* nz, G4int* iflag);
0080   void ComputeScalarFactors(G4int* type);
0081   void ComputeNextPolynomial(G4int* type);
0082   void ComputeNewEstimate(G4int type, G4double* uu, G4double* vv);
0083   void QuadraticSyntheticDivision(G4int n, G4double* u, G4double* v,
0084                                   std::vector<G4double>& p,
0085                                   std::vector<G4double>& q, G4double* a,
0086                                   G4double* b);
0087
0088  private:
0089   std::vector<G4double> p;
0090   std::vector<G4double> qp;
0091   std::vector<G4double> k;
0092   std::vector<G4double> qk;
0093   std::vector<G4double> svk;
0094
0095   G4double sr = 0.0;
0096   G4double si = 0.0;
0097   G4double u = 0.0, v = 0.0;
0098   G4double a = 0.0, b = 0.0, c = 0.0, d = 0.0;
0099   G4double a1 = 0.0, a3 = 0.0, a7 = 0.0;
0100   G4double e = 0.0, f = 0.0, g = 0.0, h = 0.0;
0101   G4double szr = 0.0, szi = 0.0;
0102   G4double lzr = 0.0, lzi = 0.0;
0103   G4int n = 0;
0104
0105   /*  The following statements set machine constants */
0106
0107   static const G4double base;
0108   static const G4double eta;
0109   static const G4double infin;
0110   static const G4double smalno;
0111   static const G4double are;
0112   static const G4double mre;
0113   static const G4double lo;
0114 };
0115
0116 #endif