scheduleProjection.h

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/**
 *
 *   Copyright (c) 2005-2021 by Pierre-Henri WUILLEMIN(@LIP6) & Christophe GONZALES(@AMU)
 *   info_at_agrum_dot_org
 *
 *  This library is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This library 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 Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this library.  If not, see <http://www.gnu.org/licenses/>.
 *
 */


/** @file
 * @brief A generic class to project efficiently a ScheduleMultiDim over a
 *subset
 * of its variables
 *
 * ScheduleProjection is a generic wrapper designed to project efficiently a
 * multidimensional schedule object over a subset of its variables.
 *
 * To be quite generic, the ScheduleProjection takes in argument the function
 * that produces the result of the projection of the multidimensional object.
 * The following code gives an example of the usage of ScheduleProjection:
 * @code
 * // a function used to project a MultiDimImplementation<float>:
 * MultiDimImplementation<float>*
 * MinPot ( const MultiDimImplementation<float>& table,
 *          const Set<const DiscreteVariable*>& del_vars ) {
 *   return new MultiDimImplementation<float> (...);
 * }
 *
 * // another function used to project a MultiDimImplementation<float>:
 * MultiDimImplementation<float>*
 * MaxPot ( const Potential<float>& table,
 *          const Set<const DiscreteVariable*>& del_vars ) {
 *   return new Potential<float> (...);
 * }
 *
 *
 * Schedule<float> schedule;
 * ScheduleMultiDim<float> t1, t2;
 * Set<const DiscreteVariable*> set1, set2;
 * ScheduleProjectionBasic<float> Proj ( MinPot );
 * ScheduleMultiDim<float> proj_table1 = Proj.project ( t1, set1, schedule );
 *
 * // change the operator to apply
 * Proj.setProjectFunction ( MaxPot );
 * ScheduleMultiDim<float> proj_table2 = Proj.project ( t2, set2, schedule );
 *
 * @endcode
 *
 * @author Christophe GONZALES(@AMU) and Pierre-Henri WUILLEMIN(@LIP6)
 */

#ifndef GUM_SCHEDULE_PROJECTION_H
#define GUM_SCHEDULE_PROJECTION_H

#include <agrum/tools/core/set.h>
#include <agrum/tools/graphicalModels/inference/scheduler/schedule.h>
#include <agrum/tools/graphicalModels/inference/scheduler/scheduleMultiDim.h>
#include <agrum/tools/variables/discreteVariable.h>
#include <utility>

namespace gum {

  template < typename GUM_SCALAR >
  class ScheduleProjection {
    public:
    // ############################################################################
    /// @name Constructors / Destructors
    // ############################################################################
    /// @{

    /// default constructor
    ScheduleProjection();

    /// copy constructor
    ScheduleProjection(const ScheduleProjection< GUM_SCALAR >&);

    /// destructor
    virtual ~ScheduleProjection();

    /// virtual constructor
    /** @return a new fresh ScheduleCombinator with the same projection
     * function. */
    virtual ScheduleProjection< GUM_SCALAR >* newFactory() const = 0;

    /// @}

    // ############################################################################
    /// @name Accessors/Modifiers
    // ############################################################################
    /// @{

    /// creates and returns the projection of the table over a subset of its
    /// vars
    /** @return a new freshly created ScheduleMultiDim which is the result of
     * the
     * projection of the table passed in argument over the set of variables
     * NOT IN del_vars
     * @warning If del_vars is precisely equal to the variables of table, the
     * result is an empty table. */
    virtual ScheduleMultiDim< GUM_SCALAR > project(const ScheduleMultiDim< GUM_SCALAR >& table,
                                                   const Set< const DiscreteVariable* >& del_vars,
                                                   Schedule< GUM_SCALAR >&               schedule)
       = 0;
    ScheduleMultiDim< GUM_SCALAR > project(const MultiDimImplementation< GUM_SCALAR >& table,
                                           const Set< const DiscreteVariable* >&       del_vars,
                                           Schedule< GUM_SCALAR >&                     schedule);
    template < template < typename > class TABLE >
    ScheduleMultiDim< GUM_SCALAR > project(const TABLE< GUM_SCALAR >&            table,
                                           const Set< const DiscreteVariable* >& del_vars,
                                           Schedule< GUM_SCALAR >&               schedule);

    /// changes the function used for projecting tables
    virtual void setProjectFunction(MultiDimImplementation< GUM_SCALAR >* (
       *proj)(const MultiDimImplementation< GUM_SCALAR >&, const Set< const DiscreteVariable* >&))
       = 0;

    /// returns the projection function currently used by the projector
    virtual MultiDimImplementation< GUM_SCALAR >* (*projectFunction())(
       const MultiDimImplementation< GUM_SCALAR >&,
       const Set< const DiscreteVariable* >&)
       = 0;

    /** @brief returns a rough estimate of the number of operations that will be
     * performed to compute the projection */
    virtual float nbOperations(const ScheduleMultiDim< GUM_SCALAR >& table,
                               const Set< const DiscreteVariable* >& del_vars,
                               const Schedule< GUM_SCALAR >&         schedule)
       = 0;
    float nbOperations(const MultiDimImplementation< GUM_SCALAR >& table,
                       const Set< const DiscreteVariable* >&       del_vars,
                       const Schedule< GUM_SCALAR >&               schedule);
    template < template < typename > class TABLE >
    float nbOperations(const TABLE< GUM_SCALAR >&            set,
                       const Set< const DiscreteVariable* >& del_vars,
                       const Schedule< GUM_SCALAR >&         schedule);

    /// returns the memory consumption used during the projection
    /** Actually, this function does not return a precise account of the memory
     * used by the multidimProjection but a rough estimate based on the size
     * of the table involved in the projection.
     * @return a pair of memory consumption: the first one is the maximum
     * amount of memory used during the combination and the second one is the
     * amount of memory still used at the end of the function ( the memory used
     * by
     * the resulting table ) */
    virtual std::pair< long, long > memoryUsage(const ScheduleMultiDim< GUM_SCALAR >& table,
                                                const Set< const DiscreteVariable* >& del_vars,
                                                const Schedule< GUM_SCALAR >&         schedule)
       = 0;
    std::pair< long, long > memoryUsage(const MultiDimImplementation< GUM_SCALAR >& table,
                                        const Set< const DiscreteVariable* >&       del_vars,
                                        const Schedule< GUM_SCALAR >&               schedule);
    template < template < typename > class TABLE >
    std::pair< long, long > memoryUsage(const TABLE< GUM_SCALAR >&            table,
                                        const Set< const DiscreteVariable* >& del_vars,
                                        const Schedule< GUM_SCALAR >&         schedule);

    /// @}

    private:
    /// to be coherent with combinations, forbid copy operators
    ScheduleProjection< GUM_SCALAR >& operator=(const ScheduleProjection< GUM_SCALAR >&);
  };

} /* namespace gum */

// always include the template implementation
#include <agrum/tools/graphicalModels/inference/scheduler/scheduleProjection_tpl.h>

#endif /* GUM_SCHEDULE_PROJECTION_H */