CMultiObjMotionOpt_Scalarization.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */

#include "nav-precomp.h"  // Precomp header

#include <mrpt/nav/reactive/CMultiObjMotionOpt_Scalarization.h>

using namespace mrpt::nav;
using namespace mrpt::utils;

IMPLEMENTS_MRPT_OBJECT(
        CMultiObjMotionOpt_Scalarization, CMultiObjectiveMotionOptimizerBase,
        mrpt::nav)

CMultiObjMotionOpt_Scalarization::CMultiObjMotionOpt_Scalarization()
        : CMultiObjectiveMotionOptimizerBase(parameters)
{
}

void CMultiObjMotionOpt_Scalarization::clear()
{
        CMultiObjectiveMotionOptimizerBase::clear();
        m_expr_scalar_formula = mrpt::math::CRuntimeCompiledExpression();
        m_expr_scalar_vars.clear();
}

void CMultiObjMotionOpt_Scalarization::loadConfigFile(
        const mrpt::utils::CConfigFileBase& c)
{
        parameters
                .CMultiObjectiveMotionOptimizerBase::TParamsBase::loadFromConfigFile(
                        c, "CMultiObjectiveMotionOptimizerBase");  // call base-member with
        // special argument
        parameters.loadFromConfigFile(c, "CMultiObjMotionOpt_Scalarization");
}

void CMultiObjMotionOpt_Scalarization::saveConfigFile(
        mrpt::utils::CConfigFileBase& c) const
{
        parameters
                .CMultiObjectiveMotionOptimizerBase::TParamsBase::saveToConfigFile(
                        c, "CMultiObjectiveMotionOptimizerBase");  // call base-member with
        // special argument
        parameters.saveToConfigFile(c, "CMultiObjMotionOpt_Scalarization");
}

int CMultiObjMotionOpt_Scalarization::impl_decide(
        const std::vector<mrpt::nav::TCandidateMovementPTG>& movs,
        TResultInfo& extra_info)
{
        std::vector<double>& final_evaluation = extra_info.final_evaluation;
        final_evaluation.clear();

        if (extra_info.score_values.empty()) return -1;  // No valid candidate

        // compile expression upon first use:
        if (m_expr_scalar_vars.empty())
        {
                // vars:
                for (const auto& c : extra_info.score_values)
                {
                        for (const auto& score : c)
                        {
                                // double & var =
                                m_expr_scalar_vars[score.first];  // create or reuse placeholder
                        }
                }

                // formula:
                m_expr_scalar_formula = mrpt::math::CRuntimeCompiledExpression();
                // Compile user-given expressions:
                try
                {
                        m_expr_scalar_formula.compile(
                                parameters.scalar_score_formula, m_expr_scalar_vars);
                }
                catch (std::exception&)
                {
                        m_expr_scalar_vars.clear();
                        throw;  // rethrow
                }
        }

        // Evaluate the formula for all candidates:
        const size_t N = extra_info.score_values.size();
        final_evaluation.assign(N, .0);
        int best_idx = -1;
        double best_val = .0;
        for (size_t i = 0; i < N; i++)
        {
                if (extra_info.score_values[i].empty())
                        continue;  // this candidate is non-eligible.

                // Update variables & evaluate formula:
                for (const auto& score : extra_info.score_values[i])
                {
                        const auto& it = m_expr_scalar_vars.find(
                                score.first);  // this should never *create* a new entry...
                        if (it == m_expr_scalar_vars.cend())
                        {
                                THROW_EXCEPTION_FMT(
                                        "Error: found unexpected (unregistered) score named `%s`.",
                                        score.first.c_str());
                        }
                        double& var = it->second;
                        var = score.second;
                }
                const double val = m_expr_scalar_formula.eval();
                extra_info.final_evaluation[i] = val;

                if (val > 0 && (best_idx == -1 || val > best_val))
                {
                        best_idx = i;
                        best_val = val;
                }
        }

        return best_idx;
}

CMultiObjMotionOpt_Scalarization::TParams::TParams() {}
void CMultiObjMotionOpt_Scalarization::TParams::loadFromConfigFile(
        const mrpt::utils::CConfigFileBase& c, const std::string& s)
{
        // TParamsBase members are already dealt elsewhere.
        MRPT_LOAD_CONFIG_VAR_REQUIRED_CS(scalar_score_formula, string);
}

void CMultiObjMotionOpt_Scalarization::TParams::saveToConfigFile(
        mrpt::utils::CConfigFileBase& c, const std::string& s) const
{
        // TParamsBase members are already dealt elsewhere.
        MRPT_SAVE_CONFIG_VAR_COMMENT(
                scalar_score_formula,
                "A formula that takes all/a subset of scores and generates a scalar "
                "global score.");
}