compute delta observed - theoretical

src/core/peptideevidence.cpp

@@ -121,7 +121,7 @@ void PeptideEvidence::setExperimentalMass(pappso::pappso_double exp_mass) {
     _exp_mass =exp_mass;
 }
 pappso::mz PeptideEvidence::getDeltaMass() const {
-    return (_peptide_sp.get()->getMz(1) - (_exp_mass+pappso::MHPLUS));
+    return ((_exp_mass+pappso::MHPLUS) - _peptide_sp.get()->getMz(1));
 }
 pappso::mz PeptideEvidence::getPpmDeltaMass() const {
     //return (_peptide_sp.get()->getMz(1) - (_exp_mass+pappso::MHPLUS));