double uSrc = helper.GetNodeU( E, srcNode, n2 );
double uTgt = helper.GetNodeU( E, tgtNode, srcNode );
double u2 = helper.GetNodeU( E, n2, srcNode );
double uSrc = helper.GetNodeU( E, srcNode, n2 );
double uTgt = helper.GetNodeU( E, tgtNode, srcNode );
double u2 = helper.GetNodeU( E, n2, srcNode );