void clear()
						{
						genes.clear();
						chromStart=-1;
						chromEnd=-1;
						positions.clear();
						sample2positions.clear();
						}
void ErrorEstimatorImpl::iterate()
{
    iterationCount_++;

    massSpreads_.clear();

    int measurementCount = int(measurements_.size());

    for (int i=0; i<measurementCount; i++)
        calculateMassSpread(measurements_[i]);

    double errorSum = 0;
    for (int i=0; i<measurementCount; i++)
        errorSum += massSpreads_[i]->error();

    error_ = sqrt(errorSum/measurementCount);

    if (outputFile_)
        output(outputFile_);
}