CMultiObjMotionOpt_Scalarization.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2020, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */

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

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

using namespace mrpt::nav;

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::expr::CRuntimeCompiledExpression();
    m_expr_scalar_vars.clear();
}

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

void CMultiObjMotionOpt_Scalarization::saveConfigFile(
    mrpt::config::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::expr::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() = default;
void CMultiObjMotionOpt_Scalarization::TParams::loadFromConfigFile(
    const mrpt::config::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::config::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.");
}