avoid nan in the spectra and vn analysis
avoid nan in the spectra and vn analysis

chunshen1987/hadronic_afterburner_toolkit,chunshen1987/hadronic_afterburner_toolkit,chunshen1987/HBTcorrelation_MCafterburner,chunshen1987/hadronic_afterburner_toolkit,chunshen1987/hadronic_afterburner_toolkit,chunshen1987/HBTcorrelation_MCafterburner,chunshen1987/HBTcorrelation_MCafterburner