statsum_t.h Source File¶

API: statsum_t.h Source File
API
//==========================================================================
//  STATSUM_T.H - part of
//                     OMNeT++/OMNEST
//            Discrete System Simulation in C++
//
//==========================================================================
 
/*--------------------------------------------------------------*
  Copyright (C) 1992-2017 Andras Varga
  Copyright (C) 2006-2017 OpenSim Ltd.
 
  This file is distributed WITHOUT ANY WARRANTY. See the file
  `license' for details on this and other legal matters.
*--------------------------------------------------------------*/
 
#ifndef __OMNETPP_STATSUM_T_H
#define __OMNETPP_STATSUM_T_H
 
#include <cmath>
#include "simkerneldefs.h"
#include "platdep/config.h"
 
namespace omnetpp {
 
namespace internals {
class SIM_API NeumaierSum
{
  private:
    double sum = 0;
    double comp = 0;  // running compensation for lost low-order bits
 
  public:
    NeumaierSum() = default;
    NeumaierSum(double val) : sum(val), comp(0) {}
    NeumaierSum& operator=(double val) { sum = val; comp = 0; return *this; }
    operator double() const { return sum + comp; }
    NeumaierSum& operator+=(double value) {
        double t = sum + value;
        if (std::abs(sum) >= std::abs(value))
            comp += (sum - t) + value;
        else
            comp += (value - t) + sum;
        sum = t;
        return *this;
    }
};
 
}  // namespace internals
 
using statsum_t = internals::NeumaierSum;
 
// Legacy mode:
// using statsum_t = double;
 
}  // namespace omnetpp
 
#endif