Evaluator.cpp

#include "Evaluator.h"
#include <cmath>
 
 
 
bool Evaluator::initialize()
{
    initFunctionNames();
    data.clear();
    values = std::vector<double>(MAX_SUBTREES,0);
    valueFlags = std::vector<bool>(MAX_SUBTREES, false);
    return true;
}
 
 
void Evaluator::initFunctionNames()
{
    termNames.clear();
    termNames.push_back("x1");
    termNames.push_back("x2");
 
    funcNames.clear();
    funcNames.push_back("+");
    funcNames.push_back("-");
    funcNames.push_back("*");
    funcNames.push_back("/");
    funcNames.push_back("sin");
    funcNames.push_back("cos");
}
 
 
double Evaluator::executeParsedExpression(uint sample, uint iTree)
{
    iExpression = iTree;
    if (iSample != sample){
        valueFlags = std::vector<bool>(MAX_SUBTREES, false); // This is VERY expensive and slows down the program
    }
    iSample = sample;
    position = -1;
    
    return execute();
}
 
 
double Evaluator::execute()
{
    position++;
 
    switch(parsedExpression[iExpression][position])
    {
        case ADD:
            return execute() + execute();
            break;
        case SUB:
            return execute() - execute();
            break;
        case MUL:
            return execute() * execute();
            break;
        case DIV: { 
            double d1 = execute();
            double d2 = execute();
            if(fabs(d2) < 0.00000001)
                return 1;
            else
                return d1/d2;
            break;
                  }
        case SIN:
            return sin(execute());
            break;
        case COS:
            return cos(execute());
            break;
        default:
            if( parsedExpression[iExpression][position] >= SUBTREES){
                // Backup variables
                uint iExpression_ = iExpression;
                uint iSample_ = iSample;
                int position_ = position;
                // Get subtree index
                uint subtree = parsedExpression[iExpression][position] - SUBTREES + 1;
                double returnValue;
                // Check whether this subtree has already been evaluated
                if (valueFlags[subtree - 1]){
                    returnValue = values[subtree - 1];
                }
                else{
                    // Execute subtree expression
                    returnValue = values[subtree - 1] = executeParsedExpression(iSample, subtree);
                    valueFlags[subtree - 1] = true;
                }
                // Restore variables
                iExpression = iExpression_;
                iSample = iSample_;
                position = position_;
                return returnValue;
            }
            else return data[iSample][parsedExpression[iExpression][position] - TERMINALS];
            break;
    }
}