1 /* 2 This file contains routines for interfacing to random number generators. 3 This provides more than just an interface to some system random number 4 generator: 5 6 Numbers can be shuffled for use as random tuples 7 8 Multiple random number generators may be used 9 10 We are still not sure what interface we want here. There should be 11 one to reinitialize and set the seed. 12 */ 13 14 #include <petsc/private/randomimpl.h> /*I "petscsys.h" I*/ 15 16 /*@ 17 PetscRandomGetValue - Generates a random number. Call this after first calling 18 `PetscRandomCreate()`. 19 20 Not Collective 21 22 Input Parameter: 23 . r - the random number generator context 24 25 Output Parameter: 26 . val - the value 27 28 Level: intermediate 29 30 Notes: 31 Use `VecSetRandom()` to set the elements of a vector to random numbers. 32 33 When PETSc is compiled for complex numbers this returns a complex number with random real and complex parts. 34 Use `PetscRandomGetValueReal()` to get a random real number. 35 36 To get a complex number with only a random real part, first call `PetscRandomSetInterval()` with a equal 37 low and high imaginary part. Similarly to get a complex number with only a random imaginary part call 38 `PetscRandomSetInterval()` with a equal low and high real part. 39 40 Example of Usage: 41 .vb 42 PetscRandomCreate(PETSC_COMM_WORLD,&r); 43 PetscRandomGetValue(r,&value1); 44 PetscRandomGetValue(r,&value2); 45 PetscRandomGetValue(r,&value3); 46 PetscRandomDestroy(&r); 47 .ve 48 49 .seealso: `PetscRandom`, `PetscRandomCreate()`, `PetscRandomDestroy()`, `VecSetRandom()`, `PetscRandomGetValueReal()`, `PetscRandomSetInterval()` 50 @*/ 51 PetscErrorCode PetscRandomGetValue(PetscRandom r, PetscScalar *val) 52 { 53 PetscFunctionBegin; 54 PetscValidHeaderSpecific(r, PETSC_RANDOM_CLASSID, 1); 55 PetscValidType(r, 1); 56 if (!r->ops->getvalue) PetscUseTypeMethod(r, getvalues, 1, val); 57 else PetscUseTypeMethod(r, getvalue, val); 58 PetscCall(PetscObjectStateIncrease((PetscObject)r)); 59 PetscFunctionReturn(PETSC_SUCCESS); 60 } 61 62 /*@ 63 PetscRandomGetValueReal - Generates a real random number. Call this after first calling 64 `PetscRandomCreate()`. 65 66 Not Collective 67 68 Input Parameter: 69 . r - the random number generator context 70 71 Output Parameter: 72 . val - the value 73 74 Level: intermediate 75 76 Note: 77 Use `VecSetRandom()` to set the elements of a vector to random numbers. 78 79 Example of Usage: 80 .vb 81 PetscRandomCreate(PETSC_COMM_WORLD,&r); 82 PetscRandomGetValueReal(r,&value1); 83 PetscRandomGetValueReal(r,&value2); 84 PetscRandomGetValueReal(r,&value3); 85 PetscRandomDestroy(&r); 86 .ve 87 88 .seealso: `PetscRandom`, `PetscRandomCreate()`, `PetscRandomDestroy()`, `VecSetRandom()`, `PetscRandomGetValue()` 89 @*/ 90 PetscErrorCode PetscRandomGetValueReal(PetscRandom r, PetscReal *val) 91 { 92 PetscFunctionBegin; 93 PetscValidHeaderSpecific(r, PETSC_RANDOM_CLASSID, 1); 94 PetscValidType(r, 1); 95 if (!r->ops->getvaluereal) PetscUseTypeMethod(r, getvaluesreal, 1, val); 96 else PetscUseTypeMethod(r, getvaluereal, val); 97 PetscCall(PetscObjectStateIncrease((PetscObject)r)); 98 PetscFunctionReturn(PETSC_SUCCESS); 99 } 100 101 /*@ 102 PetscRandomGetValues - Generates a sequence of random numbers. Call this after first calling 103 `PetscRandomCreate()`. 104 105 Not Collective 106 107 Input Parameters: 108 + r - the random number generator context 109 - n - number of random numbers to generate 110 111 Output Parameter: 112 . val - the array to hold the values 113 114 Level: intermediate 115 116 Notes: 117 Use `VecSetRandom()` to set the elements of a vector to random numbers. 118 119 When PETSc is compiled for complex numbers this returns an array of complex numbers with random real and complex parts. 120 Use `PetscRandomGetValuesReal()` to get an array of random real numbers. 121 122 .seealso: `PetscRandom`, `PetscRandomCreate()`, `PetscRandomDestroy()`, `VecSetRandom()`, `PetscRandomGetValue()` 123 @*/ 124 PetscErrorCode PetscRandomGetValues(PetscRandom r, PetscInt n, PetscScalar *val) 125 { 126 PetscFunctionBegin; 127 PetscValidHeaderSpecific(r, PETSC_RANDOM_CLASSID, 1); 128 PetscValidType(r, 1); 129 if (!r->ops->getvalues) { 130 PetscErrorCode (*const getvalue)(PetscRandom, PetscScalar *) = r->ops->getvalue; 131 132 for (PetscInt i = 0; i < n; ++i) PetscCall(getvalue(r, val + i)); 133 } else PetscUseTypeMethod(r, getvalues, n, val); 134 PetscCall(PetscObjectStateIncrease((PetscObject)r)); 135 PetscFunctionReturn(PETSC_SUCCESS); 136 } 137 138 /*@ 139 PetscRandomGetValuesReal - Generates a sequence of real random numbers. Call this after first calling 140 `PetscRandomCreate()`. 141 142 Not Collective 143 144 Input Parameters: 145 + r - the random number generator context 146 - n - number of random numbers to generate 147 148 Output Parameter: 149 . val - the array to hold the values 150 151 Level: intermediate 152 153 Note: 154 Use `VecSetRandom()` to set the elements of a vector to random numbers. 155 156 .seealso: `PetscRandom`, `PetscRandomCreate()`, `PetscRandomDestroy()`, `VecSetRandom()`, `PetscRandomGetValues()` 157 @*/ 158 PetscErrorCode PetscRandomGetValuesReal(PetscRandom r, PetscInt n, PetscReal *val) 159 { 160 PetscFunctionBegin; 161 PetscValidHeaderSpecific(r, PETSC_RANDOM_CLASSID, 1); 162 PetscValidType(r, 1); 163 if (!r->ops->getvaluesreal) { 164 PetscInt i; 165 for (i = 0; i < n; i++) PetscCall((*r->ops->getvaluereal)(r, val + i)); 166 } else PetscUseTypeMethod(r, getvaluesreal, n, val); 167 PetscCall(PetscObjectStateIncrease((PetscObject)r)); 168 PetscFunctionReturn(PETSC_SUCCESS); 169 } 170 171 /*@ 172 PetscRandomGetInterval - Gets the interval over which the random numbers 173 will be distributed. By default, this interval is [0,1). 174 175 Not Collective 176 177 Input Parameter: 178 . r - the random number generator context 179 180 Output Parameters: 181 + low - The lower bound of the interval 182 - high - The upper bound of the interval 183 184 Level: intermediate 185 186 .seealso: `PetscRandom`, `PetscRandomCreate()`, `PetscRandomSetInterval()` 187 @*/ 188 PetscErrorCode PetscRandomGetInterval(PetscRandom r, PetscScalar *low, PetscScalar *high) 189 { 190 PetscFunctionBegin; 191 PetscValidHeaderSpecific(r, PETSC_RANDOM_CLASSID, 1); 192 if (low) { 193 PetscAssertPointer(low, 2); 194 *low = r->low; 195 } 196 if (high) { 197 PetscAssertPointer(high, 3); 198 *high = r->low + r->width; 199 } 200 PetscFunctionReturn(PETSC_SUCCESS); 201 } 202 203 /*@ 204 PetscRandomSetInterval - Sets the interval over which the random numbers 205 will be distributed. By default, this interval is [0,1). 206 207 Not Collective 208 209 Input Parameters: 210 + r - the random number generator context 211 . low - The lower bound of the interval 212 - high - The upper bound of the interval 213 214 Level: intermediate 215 216 Notes: 217 for complex numbers either the real part or the imaginary part of high must be greater than its low part; or both of them can be greater. 218 219 If the real or imaginary part of low and high are the same then that value is always returned in the real or imaginary part. 220 221 .seealso: `PetscRandomCreate()`, `PetscRandomGetInterval()` 222 @*/ 223 PetscErrorCode PetscRandomSetInterval(PetscRandom r, PetscScalar low, PetscScalar high) 224 { 225 PetscFunctionBegin; 226 PetscValidHeaderSpecific(r, PETSC_RANDOM_CLASSID, 1); 227 #if defined(PETSC_USE_COMPLEX) 228 PetscCheck(PetscRealPart(low) <= PetscRealPart(high), PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "only low <= high"); 229 PetscCheck(PetscImaginaryPart(low) <= PetscImaginaryPart(high), PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "only low <= high"); 230 #else 231 PetscCheck(low < high, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "only low <= high: Instead %g %g", (double)low, (double)high); 232 #endif 233 r->low = low; 234 r->width = high - low; 235 r->iset = PETSC_TRUE; 236 PetscFunctionReturn(PETSC_SUCCESS); 237 } 238