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25 // 25 //
26 // G4Pow 26 // G4Pow
27 // 27 //
28 // Class description: 28 // Class description:
29 // 29 //
30 // Utility singleton class for the fast comput 30 // Utility singleton class for the fast computation of log and pow
31 // functions. Integer argument should be in th 31 // functions. Integer argument should be in the interval 0-512, no
32 // check is performed inside these methods for 32 // check is performed inside these methods for performance reasons.
33 // For factorial integer argument should be in 33 // For factorial integer argument should be in the interval 0-170
34 // Computations with double arguments are fast 34 // Computations with double arguments are fast for the interval
35 // 0.002-511.5 for all functions except expone 35 // 0.002-511.5 for all functions except exponent, which is computed
36 // for the interval 0-84.4, standard library i 36 // for the interval 0-84.4, standard library is used in the opposite case
37 37
38 // Author: Vladimir Ivanchenko, 23.05.2009 38 // Author: Vladimir Ivanchenko, 23.05.2009
39 // ------------------------------------------- 39 // --------------------------------------------------------------------
40 #ifndef G4Pow_hh 40 #ifndef G4Pow_hh
41 #define G4Pow_hh 1 41 #define G4Pow_hh 1
42 42
43 #include "G4DataVector.hh" 43 #include "G4DataVector.hh"
44 #include "G4Exp.hh" 44 #include "G4Exp.hh"
45 #include "G4Log.hh" 45 #include "G4Log.hh"
46 #include "globals.hh" 46 #include "globals.hh"
47 47
48 class G4Pow 48 class G4Pow
49 { 49 {
50 public: 50 public:
51 static G4Pow* GetInstance(); 51 static G4Pow* GetInstance();
52 ~G4Pow() = default; 52 ~G4Pow() = default;
53 53
54 // Fast computation of Z^1/3 54 // Fast computation of Z^1/3
55 // 55 //
56 inline G4double Z13(G4int Z) const; 56 inline G4double Z13(G4int Z) const;
57 G4double A13(G4double A) const; 57 G4double A13(G4double A) const;
58 58
59 // Fast computation of Z^2/3 59 // Fast computation of Z^2/3
60 // 60 //
61 inline G4double Z23(G4int Z) const; 61 inline G4double Z23(G4int Z) const;
62 inline G4double A23(G4double A) const; 62 inline G4double A23(G4double A) const;
63 63
64 // Fast computation of log(Z) 64 // Fast computation of log(Z)
65 // 65 //
66 inline G4double logZ(G4int Z) const; 66 inline G4double logZ(G4int Z) const;
67 inline G4double logA(G4double A) const; 67 inline G4double logA(G4double A) const;
68 inline G4double logX(G4double x) const; 68 inline G4double logX(G4double x) const;
69 69
70 // Fast computation of log10(Z) 70 // Fast computation of log10(Z)
71 // 71 //
72 inline G4double log10Z(G4int Z) const; 72 inline G4double log10Z(G4int Z) const;
73 inline G4double log10A(G4double A) const; 73 inline G4double log10A(G4double A) const;
74 74
75 // Fast computation of exp(X) 75 // Fast computation of exp(X)
76 // 76 //
77 inline G4double expA(G4double A) const; 77 inline G4double expA(G4double A) const;
78 78
79 // Fast computation of pow(Z,X) 79 // Fast computation of pow(Z,X)
80 // 80 //
81 inline G4double powZ(G4int Z, G4double y) co 81 inline G4double powZ(G4int Z, G4double y) const;
82 inline G4double powA(G4double A, G4double y) 82 inline G4double powA(G4double A, G4double y) const;
83 G4double powN(G4double x, G4int n) const; 83 G4double powN(G4double x, G4int n) const;
84 84
85 // Fast factorial 85 // Fast factorial
86 // 86 //
87 inline G4double factorial(G4int Z) const; 87 inline G4double factorial(G4int Z) const;
88 inline G4double logfactorial(G4int Z) const; 88 inline G4double logfactorial(G4int Z) const;
89 89
90 private: 90 private:
91 G4Pow(); 91 G4Pow();
92 92
93 G4double A13Low(const G4double, const G4bool 93 G4double A13Low(const G4double, const G4bool) const;
94 G4double A13High(const G4double, const G4boo 94 G4double A13High(const G4double, const G4bool) const;
95 95
96 inline G4double logBase(G4double x) const; 96 inline G4double logBase(G4double x) const;
97 97
98 static G4Pow* fpInstance; 98 static G4Pow* fpInstance;
99 99
100 const G4double onethird = 1.0 / 3.0; 100 const G4double onethird = 1.0 / 3.0;
101 const G4int max2 = 5; 101 const G4int max2 = 5;
102 102
103 G4double maxA; 103 G4double maxA;
104 G4double maxLowA; 104 G4double maxLowA;
105 G4double maxA2; 105 G4double maxA2;
106 G4double maxAexp; 106 G4double maxAexp;
107 107
108 G4DataVector ener; 108 G4DataVector ener;
109 G4DataVector logen; 109 G4DataVector logen;
110 G4DataVector pz13; 110 G4DataVector pz13;
111 G4DataVector lowa13; 111 G4DataVector lowa13;
112 G4DataVector lz; 112 G4DataVector lz;
113 G4DataVector lz2; 113 G4DataVector lz2;
114 G4DataVector fexp; 114 G4DataVector fexp;
115 G4DataVector fact; 115 G4DataVector fact;
116 G4DataVector logfact; 116 G4DataVector logfact;
117 }; 117 };
118 118
119 // ----------------------------- 119 // -----------------------------
120 // Inline methods implementation 120 // Inline methods implementation
121 // ----------------------------- 121 // -----------------------------
122 122
123 inline G4double G4Pow::Z13(G4int Z) const { re 123 inline G4double G4Pow::Z13(G4int Z) const { return pz13[Z]; }
124 124
125 inline G4double G4Pow::Z23(G4int Z) const 125 inline G4double G4Pow::Z23(G4int Z) const
126 { 126 {
127 G4double x = Z13(Z); 127 G4double x = Z13(Z);
128 return x * x; 128 return x * x;
129 } 129 }
130 130
131 inline G4double G4Pow::A23(G4double A) const 131 inline G4double G4Pow::A23(G4double A) const
132 { 132 {
133 G4double x = A13(A); 133 G4double x = A13(A);
134 return x * x; 134 return x * x;
135 } 135 }
136 136
137 inline G4double G4Pow::logZ(G4int Z) const { r 137 inline G4double G4Pow::logZ(G4int Z) const { return lz[Z]; }
138 138
139 inline G4double G4Pow::logBase(G4double a) con 139 inline G4double G4Pow::logBase(G4double a) const
140 { 140 {
141 G4double res; 141 G4double res;
142 if(a <= maxA2) 142 if(a <= maxA2)
143 { 143 {
144 G4int i = G4int(max2 * (a - 1) + 0.5); 144 G4int i = G4int(max2 * (a - 1) + 0.5);
145 if(i > max2) 145 if(i > max2)
146 { 146 {
147 i = max2; 147 i = max2;
148 } 148 }
149 G4double x = a / (G4double(i) / max2 + 1) 149 G4double x = a / (G4double(i) / max2 + 1) - 1;
150 res = lz2[i] + x * (1.0 - (0.5 - on 150 res = lz2[i] + x * (1.0 - (0.5 - onethird * x) * x);
151 } 151 }
152 else if(a <= maxA) 152 else if(a <= maxA)
153 { 153 {
154 G4int i = G4int(a + 0.5); 154 G4int i = G4int(a + 0.5);
155 G4double x = a / G4double(i) - 1; 155 G4double x = a / G4double(i) - 1;
156 res = lz[i] + x * (1.0 - (0.5 - one 156 res = lz[i] + x * (1.0 - (0.5 - onethird * x) * x);
157 } 157 }
158 else 158 else
159 { 159 {
160 res = G4Log(a); 160 res = G4Log(a);
161 } 161 }
162 return res; 162 return res;
163 } 163 }
164 164
165 inline G4double G4Pow::logA(G4double A) const 165 inline G4double G4Pow::logA(G4double A) const
166 { 166 {
167 return (1.0 <= A ? logBase(A) : -logBase(1. 167 return (1.0 <= A ? logBase(A) : -logBase(1. / A));
168 } 168 }
169 169
170 inline G4double G4Pow::logX(G4double x) const 170 inline G4double G4Pow::logX(G4double x) const
171 { 171 {
172 G4double res = 0.0; 172 G4double res = 0.0;
173 G4double a = (1.0 <= x) ? x : 1.0 / x; 173 G4double a = (1.0 <= x) ? x : 1.0 / x;
174 174
175 if(a <= maxA) 175 if(a <= maxA)
176 { 176 {
177 res = logBase(a); 177 res = logBase(a);
178 } 178 }
179 else if(a <= ener[2]) 179 else if(a <= ener[2])
180 { 180 {
181 res = logen[1] + logBase(a / ener[1]); 181 res = logen[1] + logBase(a / ener[1]);
182 } 182 }
183 else if(a <= ener[3]) 183 else if(a <= ener[3])
184 { 184 {
185 res = logen[2] + logBase(a / ener[2]); 185 res = logen[2] + logBase(a / ener[2]);
186 } 186 }
187 else 187 else
188 { 188 {
189 res = G4Log(a); 189 res = G4Log(a);
190 } 190 }
191 191
192 if(1.0 > x) 192 if(1.0 > x)
193 { 193 {
194 res = -res; 194 res = -res;
195 } 195 }
196 return res; 196 return res;
197 } 197 }
198 198
199 inline G4double G4Pow::log10Z(G4int Z) const { 199 inline G4double G4Pow::log10Z(G4int Z) const { return lz[Z] / lz[10]; }
200 200
201 inline G4double G4Pow::log10A(G4double A) cons 201 inline G4double G4Pow::log10A(G4double A) const { return logX(A) / lz[10]; }
202 202
203 inline G4double G4Pow::expA(G4double A) const 203 inline G4double G4Pow::expA(G4double A) const
204 { 204 {
205 G4double res; 205 G4double res;
206 G4double a = (0.0 <= A) ? A : -A; 206 G4double a = (0.0 <= A) ? A : -A;
207 207
208 if(a <= maxAexp) 208 if(a <= maxAexp)
209 { 209 {
210 G4int i = G4int(2 * a + 0.5); 210 G4int i = G4int(2 * a + 0.5);
211 G4double x = a - i * 0.5; 211 G4double x = a - i * 0.5;
212 res = fexp[i] * (1.0 + x * (1.0 + 0 212 res = fexp[i] * (1.0 + x * (1.0 + 0.5 * (1.0 + onethird * x) * x));
213 } 213 }
214 else 214 else
215 { 215 {
216 res = G4Exp(a); 216 res = G4Exp(a);
217 } 217 }
218 if(0.0 > A) 218 if(0.0 > A)
219 { 219 {
220 res = 1.0 / res; 220 res = 1.0 / res;
221 } 221 }
222 return res; 222 return res;
223 } 223 }
224 224
225 inline G4double G4Pow::powZ(G4int Z, G4double 225 inline G4double G4Pow::powZ(G4int Z, G4double y) const
226 { 226 {
227 return expA(y * lz[Z]); 227 return expA(y * lz[Z]);
228 } 228 }
229 229
230 inline G4double G4Pow::powA(G4double A, G4doub 230 inline G4double G4Pow::powA(G4double A, G4double y) const
231 { 231 {
232 return (0.0 == A ? 0.0 : expA(y * logX(A))); 232 return (0.0 == A ? 0.0 : expA(y * logX(A)));
233 } 233 }
234 234
235 inline G4double G4Pow::factorial(G4int Z) cons 235 inline G4double G4Pow::factorial(G4int Z) const { return fact[Z]; }
236 236
237 inline G4double G4Pow::logfactorial(G4int Z) c 237 inline G4double G4Pow::logfactorial(G4int Z) const { return logfact[Z]; }
238 238
239 #endif 239 #endif
240 240