diff --git a/src/cluster/cluster.cpp b/src/cluster/cluster.cpp
index c8aa1da3c685a489a4fcb2857c592723a2773ff0..42a0c4c913a2e10377f86b824b888a36eb56b1b4 100644
--- a/src/cluster/cluster.cpp
+++ b/src/cluster/cluster.cpp
@@ -517,7 +517,7 @@ void cluster(string config_file, string data_file, string output_path) {
 		      tppoan.write(reinterpret_cast<char *>(&value), sizeof(double));
 		    }
 		  }
-		  for (int i = 0; i < 3; i++) {
+		  for (int i = 0; i < 2; i++) {
 		    double value = c1ao->scscm[i];
 		    tppoan.write(reinterpret_cast<char *>(&value), sizeof(double));
 		    value = c1ao->scscpm[i].real();