round using 3 digits before selecting 2 digits

src/cpp/libgroupingprotein/gp_engine.cpp

@@ -175,6 +175,8 @@ Sample* GpEngine::getSampleInstance(QString name) {
 
 Peptide * GpEngine::getPeptideInstance(QString seq, gp_double mh) {
     std::map<QString, Peptide*>::iterator it;
+    //round 3 digits before:
+    mh = round(mh * (gp_double)1000)/(gp_double) 1000;
     QString data = seq.replace("L", "I") + QString("|%1").arg((unsigned long) round(mh * 100));
     it = this->_peptideList.find(data);
     if (it != _peptideList.end()) {