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25 // 25 //
26 // G4Pow << 26 //
>> 27 //
>> 28 // -------------------------------------------------------------------
>> 29 //
>> 30 // Class G4Pow
27 // 31 //
28 // Class description: 32 // Class description:
29 // 33 //
30 // Utility singleton class for the fast comput 34 // Utility singleton class for the fast computation of log and pow
31 // functions. Integer argument should be in th << 35 // functions. Integer argument should in the interval 0-512, no
32 // check is performed inside these methods for 36 // check is performed inside these methods for performance reasons.
33 // For factorial integer argument should be in 37 // For factorial integer argument should be in the interval 0-170
34 // Computations with double arguments are fast 38 // Computations with double arguments are fast for the interval
35 // 0.002-511.5 for all functions except expone << 39 // 0.002-511.5 for all functions except exponent, which is computed
36 // for the interval 0-84.4, standard library i 40 // for the interval 0-84.4, standard library is used in the opposite case
37 41
38 // Author: Vladimir Ivanchenko, 23.05.2009 << 42 // Author: Vladimir Ivanchenko
39 // ------------------------------------------- << 43 //
40 #ifndef G4Pow_hh << 44 // Creation date: 23.05.2009
41 #define G4Pow_hh 1 << 45 // -------------------------------------------------------------------
>> 46
>> 47 #ifndef G4Pow_h
>> 48 #define G4Pow_h 1
42 49
43 #include "G4DataVector.hh" <<
44 #include "G4Exp.hh" <<
45 #include "G4Log.hh" <<
46 #include "globals.hh" 50 #include "globals.hh"
>> 51 #include "G4Log.hh"
>> 52 #include "G4Exp.hh"
>> 53 #include "G4DataVector.hh"
47 54
48 class G4Pow 55 class G4Pow
49 { 56 {
50 public: << 57
51 static G4Pow* GetInstance(); << 58 public:
52 ~G4Pow() = default; << 59
53 << 60 static G4Pow* GetInstance();
54 // Fast computation of Z^1/3 << 61 ~G4Pow();
55 // << 62
56 inline G4double Z13(G4int Z) const; << 63 // Fast computation of Z^1/3
57 G4double A13(G4double A) const; << 64 //
58 << 65 inline G4double Z13(G4int Z) const;
59 // Fast computation of Z^2/3 << 66 G4double A13(G4double A) const;
60 // << 67
61 inline G4double Z23(G4int Z) const; << 68 // Fast computation of Z^2/3
62 inline G4double A23(G4double A) const; << 69 //
63 << 70 inline G4double Z23(G4int Z) const;
64 // Fast computation of log(Z) << 71 inline G4double A23(G4double A) const;
65 // << 72
66 inline G4double logZ(G4int Z) const; << 73 // Fast computation of log(Z)
67 inline G4double logA(G4double A) const; << 74 //
68 inline G4double logX(G4double x) const; << 75 inline G4double logZ(G4int Z) const;
69 << 76 inline G4double logA(G4double A) const;
70 // Fast computation of log10(Z) << 77 inline G4double logX(G4double x) const;
71 // << 78
72 inline G4double log10Z(G4int Z) const; << 79 // Fast computation of log10(Z)
73 inline G4double log10A(G4double A) const; << 80 //
74 << 81 inline G4double log10Z(G4int Z) const;
75 // Fast computation of exp(X) << 82 inline G4double log10A(G4double A) const;
76 // << 83
77 inline G4double expA(G4double A) const; << 84 // Fast computation of exp(X)
78 << 85 //
79 // Fast computation of pow(Z,X) << 86 inline G4double expA(G4double A) const;
80 // << 87
81 inline G4double powZ(G4int Z, G4double y) co << 88 // Fast computation of pow(Z,X)
82 inline G4double powA(G4double A, G4double y) << 89 //
83 G4double powN(G4double x, G4int n) const; << 90 inline G4double powZ(G4int Z, G4double y) const;
84 << 91 inline G4double powA(G4double A, G4double y) const;
85 // Fast factorial << 92 G4double powN(G4double x, G4int n) const;
86 // << 93
87 inline G4double factorial(G4int Z) const; << 94 // Fast factorial
88 inline G4double logfactorial(G4int Z) const; << 95 //
89 << 96 inline G4double factorial(G4int Z) const;
90 private: << 97 inline G4double logfactorial(G4int Z) const;
91 G4Pow(); << 98
92 << 99 private:
93 G4double A13Low(const G4double, const G4bool << 100
94 G4double A13High(const G4double, const G4boo << 101 G4Pow();
95 << 102
96 inline G4double logBase(G4double x) const; << 103 G4double A13Low(const G4double, const bool) const;
97 << 104 G4double A13High(const G4double, const bool) const;
98 static G4Pow* fpInstance; << 105
99 << 106 inline G4double logBase(G4double x) const;
100 const G4double onethird = 1.0 / 3.0; << 107
101 const G4int max2 = 5; << 108 static G4Pow* fpInstance;
102 << 109
103 G4double maxA; << 110 const G4double onethird;
104 G4double maxLowA; << 111 const G4int max2;
105 G4double maxA2; << 112
106 G4double maxAexp; << 113 G4double maxA;
107 << 114 G4double maxLowA;
108 G4DataVector ener; << 115 G4double maxA2;
109 G4DataVector logen; << 116 G4double maxAexp;
110 G4DataVector pz13; << 117
111 G4DataVector lowa13; << 118 G4DataVector ener;
112 G4DataVector lz; << 119 G4DataVector logen;
113 G4DataVector lz2; << 120 G4DataVector pz13;
114 G4DataVector fexp; << 121 G4DataVector lowa13;
115 G4DataVector fact; << 122 G4DataVector lz;
116 G4DataVector logfact; << 123 G4DataVector lz2;
>> 124 G4DataVector fexp;
>> 125 G4DataVector fact;
>> 126 G4DataVector logfact;
117 }; 127 };
118 128
119 // ----------------------------- << 129 // -------------------------------------------------------------------
120 // Inline methods implementation <<
121 // ----------------------------- <<
122 130
123 inline G4double G4Pow::Z13(G4int Z) const { re << 131 inline G4double G4Pow::Z13(G4int Z) const
>> 132 {
>> 133 return pz13[Z];
>> 134 }
124 135
125 inline G4double G4Pow::Z23(G4int Z) const 136 inline G4double G4Pow::Z23(G4int Z) const
126 { 137 {
127 G4double x = Z13(Z); 138 G4double x = Z13(Z);
128 return x * x; << 139 return x*x;
129 } 140 }
130 141
131 inline G4double G4Pow::A23(G4double A) const 142 inline G4double G4Pow::A23(G4double A) const
132 { 143 {
133 G4double x = A13(A); 144 G4double x = A13(A);
134 return x * x; << 145 return x*x;
135 } 146 }
136 147
137 inline G4double G4Pow::logZ(G4int Z) const { r << 148 inline G4double G4Pow::logZ(G4int Z) const
>> 149 {
>> 150 return lz[Z];
>> 151 }
138 152
139 inline G4double G4Pow::logBase(G4double a) con 153 inline G4double G4Pow::logBase(G4double a) const
140 { 154 {
141 G4double res; 155 G4double res;
142 if(a <= maxA2) << 156 if(a <= maxA2)
143 { 157 {
144 G4int i = G4int(max2 * (a - 1) + 0.5); << 158 G4int i = G4int(max2*(a - 1) + 0.5);
145 if(i > max2) << 159 if(i > max2) { i = max2; }
146 { << 160 G4double x = a/(G4double(i)/max2 + 1) - 1;
147 i = max2; << 161 res = lz2[i] + x*(1.0 - (0.5 - onethird*x)*x);
148 } <<
149 G4double x = a / (G4double(i) / max2 + 1) <<
150 res = lz2[i] + x * (1.0 - (0.5 - on <<
151 } 162 }
152 else if(a <= maxA) 163 else if(a <= maxA)
153 { 164 {
154 G4int i = G4int(a + 0.5); << 165 G4int i = G4int(a + 0.5);
155 G4double x = a / G4double(i) - 1; << 166 G4double x = a/G4double(i) - 1;
156 res = lz[i] + x * (1.0 - (0.5 - one << 167 res = lz[i] + x*(1.0 - (0.5 - onethird*x)*x);
157 } 168 }
158 else 169 else
159 { 170 {
160 res = G4Log(a); 171 res = G4Log(a);
161 } 172 }
162 return res; 173 return res;
163 } 174 }
164 175
165 inline G4double G4Pow::logA(G4double A) const 176 inline G4double G4Pow::logA(G4double A) const
166 { 177 {
167 return (1.0 <= A ? logBase(A) : -logBase(1. << 178 return (1.0 <= A ? logBase(A) : -logBase(1./A));
168 } 179 }
169 180
170 inline G4double G4Pow::logX(G4double x) const 181 inline G4double G4Pow::logX(G4double x) const
171 { 182 {
172 G4double res = 0.0; 183 G4double res = 0.0;
173 G4double a = (1.0 <= x) ? x : 1.0 / x; << 184 G4double a = (1.0 <= x) ? x : 1.0/x;
174 185
175 if(a <= maxA) << 186 if(a <= maxA)
176 { 187 {
177 res = logBase(a); 188 res = logBase(a);
178 } 189 }
179 else if(a <= ener[2]) 190 else if(a <= ener[2])
180 { 191 {
181 res = logen[1] + logBase(a / ener[1]); << 192 res = logen[1] + logBase(a/ener[1]);
182 } 193 }
183 else if(a <= ener[3]) 194 else if(a <= ener[3])
184 { 195 {
185 res = logen[2] + logBase(a / ener[2]); << 196 res = logen[2] + logBase(a/ener[2]);
186 } 197 }
187 else 198 else
188 { 199 {
189 res = G4Log(a); 200 res = G4Log(a);
190 } 201 }
191 202
192 if(1.0 > x) << 203 if(1.0 > x) { res = -res; }
193 { <<
194 res = -res; <<
195 } <<
196 return res; 204 return res;
197 } 205 }
198 206
199 inline G4double G4Pow::log10Z(G4int Z) const { << 207 inline G4double G4Pow::log10Z(G4int Z) const
>> 208 {
>> 209 return lz[Z]/lz[10];
>> 210 }
200 211
201 inline G4double G4Pow::log10A(G4double A) cons << 212 inline G4double G4Pow::log10A(G4double A) const
>> 213 {
>> 214 return logX(A)/lz[10];
>> 215 }
202 216
203 inline G4double G4Pow::expA(G4double A) const 217 inline G4double G4Pow::expA(G4double A) const
204 { 218 {
205 G4double res; 219 G4double res;
206 G4double a = (0.0 <= A) ? A : -A; 220 G4double a = (0.0 <= A) ? A : -A;
207 221
208 if(a <= maxAexp) 222 if(a <= maxAexp)
209 { 223 {
210 G4int i = G4int(2 * a + 0.5); << 224 G4int i = G4int(2*a + 0.5);
211 G4double x = a - i * 0.5; << 225 G4double x = a - i*0.5;
212 res = fexp[i] * (1.0 + x * (1.0 + 0 << 226 res = fexp[i]*(1.0 + x*(1.0 + 0.5*(1.0 + onethird*x)*x));
213 } 227 }
214 else 228 else
215 { 229 {
216 res = G4Exp(a); 230 res = G4Exp(a);
217 } 231 }
218 if(0.0 > A) << 232 if(0.0 > A) { res = 1.0/res; }
219 { <<
220 res = 1.0 / res; <<
221 } <<
222 return res; 233 return res;
223 } 234 }
224 235
225 inline G4double G4Pow::powZ(G4int Z, G4double 236 inline G4double G4Pow::powZ(G4int Z, G4double y) const
226 { 237 {
227 return expA(y * lz[Z]); << 238 return expA(y*lz[Z]);
228 } 239 }
229 240
230 inline G4double G4Pow::powA(G4double A, G4doub 241 inline G4double G4Pow::powA(G4double A, G4double y) const
231 { 242 {
232 return (0.0 == A ? 0.0 : expA(y * logX(A))); << 243 return (0.0 == A ? 0.0 : expA(y*logX(A)));
233 } 244 }
234 245
235 inline G4double G4Pow::factorial(G4int Z) cons << 246 inline G4double G4Pow::factorial(G4int Z) const
>> 247 {
>> 248 return fact[Z];
>> 249 }
>> 250
>> 251 inline G4double G4Pow::logfactorial(G4int Z) const
>> 252 {
>> 253 return logfact[Z];
>> 254 }
236 255
237 inline G4double G4Pow::logfactorial(G4int Z) c << 256 // -------------------------------------------------------------------
238 257
239 #endif 258 #endif
240 259