diff --git a/edo/src/edoNormalAdaptive.h b/edo/src/edoNormalAdaptive.h
index 85db27b53..7c6e80a6c 100644
--- a/edo/src/edoNormalAdaptive.h
+++ b/edo/src/edoNormalAdaptive.h
@@ -44,7 +44,7 @@ public:
     typedef Eigen::Matrix< AtomType, Eigen::Dynamic, 1> Vector; // column vectors ( n lines, 1 column)
     typedef Eigen::Matrix< AtomType, Eigen::Dynamic, Eigen::Dynamic> Matrix;
 
-    edoNormalAdaptive( unsigned int dim ) :
+    edoNormalAdaptive( unsigned int dim = 1 ) :
         _dim(dim),
         _mean( Vector::Zero(dim) ),
         _C( Matrix::Identity(dim,dim) ),
@@ -57,7 +57,7 @@ public:
         assert( _dim > 0);
     }
 
-    edoNormalAdaptive( unsigned int dim, 
+    edoNormalAdaptive( unsigned int dim,
             Vector mean,
             Matrix C,
             Matrix B,
diff --git a/edo/src/edoNormalMulti.h b/edo/src/edoNormalMulti.h
index db36810a0..2736cd45b 100644
--- a/edo/src/edoNormalMulti.h
+++ b/edo/src/edoNormalMulti.h
@@ -45,6 +45,15 @@ class edoNormalMulti : public edoDistrib< EOT >
 public:
     typedef typename EOT::AtomType AtomType;
 
+    edoNormalMulti( unsigned int dim = 1 ) :
+            _mean( const ublas::vector<AtomType>(0,dim)        ),
+        _varcovar( const ublas::identity_matrix<AtomType>(dim) )
+    {
+        assert(_mean.size() > 0);
+        assert(_mean.size() == _varcovar.size1());
+        assert(_mean.size() == _varcovar.size2());
+    }
+
     edoNormalMulti
     (
      const ublas::vector< AtomType >& mean,
@@ -86,6 +95,15 @@ public:
     typedef Eigen::Matrix< AtomType, Eigen::Dynamic, 1> Vector;
     typedef Eigen::Matrix< AtomType, Eigen::Dynamic, Eigen::Dynamic> Matrix;
 
+    edoNormalMulti( unsigned int dim = 1 ) :
+            _mean( Vector::Zero(dim) ),
+        _varcovar( Matrix::Identity(dim,dim) )
+    {
+        assert(_mean.size() > 0);
+        assert(_mean.size() == _varcovar.size1());
+        assert(_mean.size() == _varcovar.size2());
+    }
+
     edoNormalMulti(
         const Vector & mean,
         const Matrix & varcovar