diff --git a/matlab/ps_load_initial_gamma.m b/matlab/ps_load_initial_gamma.m
index fb891d9..a3aadfd 100644
--- a/matlab/ps_load_initial_gamma.m
+++ b/matlab/ps_load_initial_gamma.m
@@ -67,7 +67,10 @@
 master_day=datenum(year,month,monthday);
 
 master_ix=sum(day<master_day)+1;
-if day(master_ix)~=master_day
+if master_ix > length(day)
+    master_master_flag='0' % no null master-master ifg provided
+    day=[day;master_day];
+elseif day(master_ix)~=master_day
     master_master_flag='0' % no null master-master ifg provided
     day=[day(1:master_ix-1);master_day;day(master_ix:end)];
 else