diff --git a/benchmarks/dvmp/analysis/vm_invar.cxx b/benchmarks/dvmp/analysis/vm_invar.cxx
index 7ce7dbfe149af47a5d2d84fd0031b535117c15a5..8628aa4fb8ffcd1e048d52fa84989d987e71896f 100644
--- a/benchmarks/dvmp/analysis/vm_invar.cxx
+++ b/benchmarks/dvmp/analysis/vm_invar.cxx
@@ -178,7 +178,7 @@ int vm_invar(const std::string& config_name)
       }
       histTitles[i][j] = histTitles[i][j] + ";#";
       //construct RawhistName
-      RawhistName[i] = VarName[i] + "_" + VarCate[j];
+      RawhistName[i][j] = VarName[i] + "_" + VarCate[j];
       //get histograms
       auto h_tmp = d_im.Histo1D({fmt::format("{}_tmp", histName[i][j]).c_str(), histTitles[i][j].c_str(), 50, range_l[i][j], range_h[i][j]}, RawhistName[i][j].c_str());
       TH1D* hptr_tmp = &(*h_tmp);