[decoupled adaptive] store copy, not reference.

See FS#240.

Approved by natalies.



git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@13511 2fb0f335-1f38-0410-981e-8018bf24f1b0

dumux/decoupled/2p/impes/gridadaptionindicator2plocalflux.hh

@@ -338,7 +338,7 @@ public:
                     ReferenceElements::general(eIt->geometry().type()).position(0, 0);
 
                 // get the transposed Jacobian of the element mapping
-                const DimMatrix& jacobianT = eIt->geometry().jacobianTransposed(localPos);
+                const DimMatrix jacobianT = eIt->geometry().jacobianTransposed(localPos);
 
                 // calculate the element velocity by the Piola transformation
                 DimVector elementVelocity(0);