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#ifndef STORM_SOLVER_SYMBOLICLINEAREQUATIONSOLVER_H_
#define STORM_SOLVER_SYMBOLICLINEAREQUATIONSOLVER_H_
#include <memory>
#include <set>
#include <vector>
#include <boost/variant.hpp>
#include "src/storage/expressions/Variable.h"
#include "src/storage/dd/DdType.h"
namespace storm {
namespace dd {
template<storm::dd::DdType Type, typename ValueType>
class Add;
template<storm::dd::DdType Type>
class Bdd;
}
namespace solver {
/*!
* An interface that represents an abstract symbolic linear equation solver. In addition to solving a system of
* linear equations, the functionality to repeatedly multiply a matrix with a given vector is provided.
*/
template<storm::dd::DdType DdType, typename ValueType = double>
class SymbolicLinearEquationSolver {
public:
/*!
* Constructs a symbolic linear equation solver with the given meta variable sets and pairs.
*
* @param A The matrix defining the coefficients of the linear equation system.
* @param diagonal An ADD characterizing the elements on the diagonal of the matrix.
* @param allRows A BDD characterizing all rows of the equation system.
* @param rowMetaVariables The meta variables used to encode the rows of the matrix.
* @param columnMetaVariables The meta variables used to encode the columns of the matrix.
* @param rowColumnMetaVariablePairs The pairs of row meta variables and the corresponding column meta
* variables.
*/
SymbolicLinearEquationSolver(storm::dd::Add<DdType, ValueType> const& A, storm::dd::Bdd<DdType> const& allRows, std::set<storm::expressions::Variable> const& rowMetaVariables, std::set<storm::expressions::Variable> const& columnMetaVariables, std::vector<std::pair<storm::expressions::Variable, storm::expressions::Variable>> const& rowColumnMetaVariablePairs);
/*!
* Constructs a symbolic linear equation solver with the given meta variable sets and pairs.
*
* @param A The matrix defining the coefficients of the linear equation system.
* @param allRows A BDD characterizing all rows of the equation system.
* @param rowMetaVariables The meta variables used to encode the rows of the matrix.
* @param columnMetaVariables The meta variables used to encode the columns of the matrix.
* @param rowColumnMetaVariablePairs The pairs of row meta variables and the corresponding column meta
* variables.
* @param precision The precision to achieve.
* @param maximalNumberOfIterations The maximal number of iterations to perform when solving a linear
* equation system iteratively.
* @param relative Sets whether or not to use a relativ stopping criterion rather than an absolute one.
*/
SymbolicLinearEquationSolver(storm::dd::Add<DdType, ValueType> const& A, storm::dd::Bdd<DdType> const& allRows, std::set<storm::expressions::Variable> const& rowMetaVariables, std::set<storm::expressions::Variable> const& columnMetaVariables, std::vector<std::pair<storm::expressions::Variable, storm::expressions::Variable>> const& rowColumnMetaVariablePairs, double precision, uint_fast64_t maximalNumberOfIterations, bool relative);
/*!
* Solves the equation system A*x = b. The matrix A is required to be square and have a unique solution.
* The solution of the set of linear equations will be written to the vector x. Note that the matrix A has
* to be given upon construction time of the solver object.
*
* @param x The initial guess for the solution vector. Its length must be equal to the number of rows of A.
* @param b The right-hand side of the equation system. Its length must be equal to the number of rows of A.
* @return The solution of the equation system.
*/
virtual storm::dd::Add<DdType, ValueType> solveEquations(storm::dd::Add<DdType, ValueType> const& x, storm::dd::Add<DdType, ValueType> const& b) const;
/*!
* Performs repeated matrix-vector multiplication, using x[0] = x and x[i + 1] = A*x[i] + b. After
* performing the necessary multiplications, the result is written to the input vector x. Note that the
* matrix A has to be given upon construction time of the solver object.
*
* @param x The initial vector with which to perform matrix-vector multiplication. Its length must be equal
* to the number of rows of A.
* @param b If non-null, this vector is added after each multiplication. If given, its length must be equal
* to the number of rows of A.
* @return The solution of the equation system.
*/
virtual storm::dd::Add<DdType, ValueType> multiply(storm::dd::Add<DdType, ValueType> const& x, storm::dd::Add<DdType, ValueType> const* b = nullptr, uint_fast64_t n = 1) const;
protected:
// The matrix defining the coefficients of the linear equation system.
storm::dd::Add<DdType, ValueType> const& A;
// A BDD characterizing all rows of the equation system.
storm::dd::Bdd<DdType> const& allRows;
// The row variables.
std::set<storm::expressions::Variable> rowMetaVariables;
// The column variables.
std::set<storm::expressions::Variable> columnMetaVariables;
// The pairs of meta variables used for renaming.
std::vector<std::pair<storm::expressions::Variable, storm::expressions::Variable>> const& rowColumnMetaVariablePairs;
// The precision to achive.
double precision;
// The maximal number of iterations to perform.
uint_fast64_t maximalNumberOfIterations;
// A flag indicating whether a relative or an absolute stopping criterion is to be used.
bool relative;
};
} // namespace solver
} // namespace storm
#endif /* STORM_SOLVER_SYMBOLICLINEAREQUATIONSOLVER_H_ */