Adding missing = to allow SpectrumData retrieval for index 0

radixio/spectrum.cc

@@ -245,7 +245,7 @@ void Spectrum::spectrumData(int i, std::string &title, std::string &source,
                             float &totalNeutronCount, int &numberOfChannels,
                             std::vector<float> &countsByChannel)
 {
-  if (i > 0 && i < mSpectrumData.size())
+  if (i >= 0 && i < mSpectrumData.size())
   {
     size_t i_              = size_t(i);
     SpectrumData spectrum  = mSpectrumData[i_];