#39 Handling of Lagrange Multiplier in the ImposedDrivingVariable class

[Helfer Thomas]

The terms related to the Lagrange multipliers are badly handled in the ImposedDrivingVariable:

• The sign is wrong (Thus the lagrange multipliers can't be identified to the stress).
• The residual is not updated appropriatly.

For the second point, one must do this

- r(this->c)   = a*u1(pos);
+ r(this->c) -= a*u1(pos);

Those mistakes don't have any impact on the results, but changes the values of the residual.

[Helfer Thomas]

Fixed in current revisions of rliv-2.0, rliv-3.0 and trunk.