| /*---------------------------------------------------------------------------*\ | |
| ========= | | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | |
| \\ / O peration | Website: https://openfoam.org | |
| \\ / A nd | Copyright (C) 2018-2026 OpenFOAM Foundation | |
| \\/ M anipulation | | |
| ------------------------------------------------------------------------------- | |
| License | |
| This file is part of OpenFOAM. | |
| OpenFOAM is free software: you can redistribute it and/or modify it | |
| under the terms of the GNU General Public License as published by | |
| the Free Software Foundation, either version 3 of the License, or | |
| (at your option) any later version. | |
| OpenFOAM is distributed in the hope that it will be useful, but WITHOUT | |
| ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| for more details. | |
| You should have received a copy of the GNU General Public License | |
| along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>. | |
| Class | |
| Foam::randomGenerator | |
| Description | |
| Random number generator | |
| This is a clone of the drand48 algorithm. This is significantly quicker | |
| than drand48, presumably due to the compiler inlining the sampling methods. | |
| It is also significantly quicker than the standard library linear | |
| congruential engine, as it does not use Schrage's algorithm to prevent | |
| overflow. | |
| See <http://pubs.opengroup.org/onlinepubs/007908775/xsh/drand48.html> for | |
| details of the seeding and iteration sequence. | |
| SourceFiles | |
| randomGenerator.C | |
| randomGeneratorI.H | |
| \*---------------------------------------------------------------------------*/ | |
| // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // | |
| namespace Foam | |
| { | |
| // Forward declaration of classes | |
| class Istream; | |
| class Ostream; | |
| // Forward declaration of friend functions and operators | |
| class randomGenerator; | |
| Istream& operator>>(Istream&, randomGenerator&); | |
| Ostream& operator<<(Ostream&, const randomGenerator&); | |
| /*---------------------------------------------------------------------------*\ | |
| Class randomGenerator Declaration | |
| \*---------------------------------------------------------------------------*/ | |
| class randomGenerator | |
| { | |
| public: | |
| // Public Classes | |
| //- Seed class | |
| class seed | |
| { | |
| // Private Data | |
| //- The seed value | |
| const uint64_t s_; | |
| // Private Member Functions | |
| //- Return the initial integer | |
| inline uint64_t x(const bool global) const; | |
| public: | |
| //- Allow randomGenerator to access the seed value | |
| friend class randomGenerator; | |
| // Constructors | |
| //- Construct from a label | |
| inline seed(const label s); | |
| //- Construct from a word | |
| inline seed(const word& s); | |
| }; | |
| private: | |
| // Private Static Data | |
| //- The parameters of the linear congruential iteration | |
| static const uint64_t A = 0x5DEECE66D, C = 0xB, M = uint64_t(1) << 48; | |
| // Private Data | |
| //- Is this generator global? | |
| const bool global_; | |
| //- The stored integer | |
| uint64_t x_; | |
| // Private Member Functions | |
| //- Check the state is synchronised | |
| void checkSync() const; | |
| //- Advance the state and return an integer sample | |
| inline uint64_t sample(); | |
| // Scalars | |
| //- Return a scalar uniformly distributed between zero and one. | |
| // Don't check synchronisation. | |
| inline scalar scalar01NoCheckSync(); | |
| //- Return a scalar uniformly distributed between zero and one. | |
| // Don't check synchronisation. | |
| inline scalar scalarABNoCheckSync(const scalar a, const scalar b); | |
| // Other Types | |
| //- Return a type with components uniformly distributed between | |
| // zero and one. Don't check synchronisation. | |
| template<class Type> | |
| inline Type sample01NoCheckSync(); | |
| //- Return a type with components uniformly distributed between two | |
| // limits. Don't check synchronisation. | |
| template<class Type> | |
| inline Type sampleABNoCheckSync(const Type& a, const Type& b); | |
| public: | |
| // Constructors | |
| //- Construct from a seed | |
| inline randomGenerator(const seed s, const bool global = false); | |
| //- Copy construct | |
| inline randomGenerator(const randomGenerator&); | |
| //- Move construct | |
| inline randomGenerator(randomGenerator&&); | |
| //- Construct from a stream | |
| randomGenerator(Istream& is, const bool global = false); | |
| //- Construct from a dictionary | |
| randomGenerator | |
| ( | |
| const word& name, | |
| const dictionary& dict, | |
| randomGenerator&& defaultRndGen | |
| ); | |
| //- Construct from a dictionary | |
| randomGenerator | |
| ( | |
| const word& name, | |
| const dictionary& dict, | |
| const seed defaultS, | |
| const bool global = false | |
| ); | |
| //- Destructor | |
| inline ~randomGenerator(); | |
| // Member Functions | |
| // Scalars | |
| //- Return a scalar uniformly distributed between zero and one | |
| inline scalar scalar01(); | |
| //- Return scalars uniformly distributed between zero and one | |
| inline tmp<scalarField> scalar01(const label n); | |
| //- Return a scalar uniformly distributed between two limits | |
| inline scalar scalarAB(const scalar a, const scalar b); | |
| //- Return scalars uniformly distributed between two limits | |
| inline tmp<scalarField> scalarAB | |
| ( | |
| const label n, | |
| const scalar a, | |
| const scalar b | |
| ); | |
| // Other Types | |
| //- Return a type with components uniformly distributed between | |
| // zero and one | |
| template<class Type> | |
| inline Type sample01(); | |
| //- Return types with components uniformly distributed between zero | |
| // and one | |
| template<class Type> | |
| inline tmp<Field<Type>> sample01(const label n); | |
| //- Return a type with components uniformly distributed between two | |
| // limits | |
| template<class Type> | |
| inline Type sampleAB(const Type& a, const Type& b); | |
| //- Return types with components uniformly distributed between two | |
| // limits | |
| template<class Type> | |
| inline tmp<Field<Type>> sampleAB | |
| ( | |
| const label n, | |
| const Type& a, | |
| const Type& b | |
| ); | |
| //- Randomly permute a list | |
| template<class Container> | |
| inline void permute(Container& l); | |
| //- Return a random permutation | |
| inline labelList permutation(const label n); | |
| //- Create a randomly seeded generator | |
| inline randomGenerator generator(); | |
| // Member Operators | |
| //- Copy-assignment | |
| void operator=(const randomGenerator&); | |
| //- Move-assignment | |
| void operator=(randomGenerator&&); | |
| // IOstream Operators | |
| //- Read from stream | |
| friend Istream& operator>>(Istream&, randomGenerator&); | |
| //- Write to stream | |
| friend Ostream& operator<<(Ostream&, const randomGenerator&); | |
| }; | |
| template<> | |
| inline scalar randomGenerator::sample01NoCheckSync(); | |
| template<> | |
| inline label randomGenerator::sample01NoCheckSync(); | |
| template<> | |
| inline scalar randomGenerator::sampleABNoCheckSync | |
| ( | |
| const scalar& a, | |
| const scalar& b | |
| ); | |
| template<> | |
| inline label randomGenerator::sampleABNoCheckSync | |
| ( | |
| const label& a, | |
| const label& b | |
| ); | |
| void writeEntry(Ostream& os, const randomGenerator& rndGen); | |
| // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // | |
| } // End namespace Foam | |
| // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // | |
| // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // | |
| // ************************************************************************* // | |