diff --git a/src/task-inequality.cpp b/src/task-inequality.cpp
index 92c9d3daa2053c9788dba13901896ffe03b1de24..b2d17986e91a2ff8c917670b42e6091cb1c6dc9d 100644
--- a/src/task-inequality.cpp
+++ b/src/task-inequality.cpp
@@ -165,7 +165,7 @@ namespace dynamicgraph
 	res.resize( outsize ); int idx=0;
 	for( int i=0;i<insize;++i )
 	  { if(selec(i))
-	      res(idx++) = ( error(i)-refInf(i) ) / ( error(i)-refInf(i) ); }
+	      res(idx++) = ( error(i)-refInf(i) ) / ( refSup(i)-refInf(i) ); }
 	return res;
       }