diff --git a/bisection.h b/bisection.h
new file mode 100644
index 0000000..331ffce
--- /dev/null
+++ b/bisection.h
@@ -0,0 +1,26 @@
+#ifndef _BISECTION_H
+#define _BISECTION_H
+//general bisection search
+//returns dm-1 on failure, otherwise number between dm and hm
+
+template<typename INDEX, typename COMPAR, typename SUBJECT>
+INDEX bisection_find(INDEX dm, INDEX hm, const SUBJECT *key, const SUBJECT *base , unsigned int lead_dimension_base, COMPAR (*cmp)(const SUBJECT *, const SUBJECT *)) 
+{
+if(dm>hm) return(dm-1);
+if(dm==hm) return  (*cmp)(base+dm*lead_dimension_base,key)? dm-1 :dm;
+INDEX sm;
+INDEX dm0=dm;
+--dm;
+++hm;
+do
+          {
+          sm = (dm+hm)/2;
+	  COMPAR q = (*cmp)(base+sm*lead_dimension_base,key);
+          if (!q) return(sm);
+          else if (q<0) dm = sm; else hm = sm;
+          }
+while (hm > dm+1);
+return(dm0-1);
+}
+
+#endif