compute correct tangent when using BFGS

NonLinearSolver/nlsolver/nonLinearMechSolver.cpp

@@ -3349,6 +3349,14 @@ void nonLinearMechSolver::oneStepPostSolve(const double curtime, const int numst
     // copy current to initial state
     (*_initialState) = (*_currentState);
     
+    if ((_stiffnessModificationMonitoring->quasiNewtonUpdate() and _tangentflag) and 
+        (_systemType == DISP_ELIM or _systemType == DISP_MULT))
+    {
+      Msg::Info("stiffness matrix is reevaluated");
+      this->computeStiffMatrix();
+    }
+    
+
     this->extractAverageProperties(_tangentflag);
     if (getDamageToCohesiveJumpFlag() and !_multiscaleFlag){
       this->checkFailureOnset();
@@ -10821,7 +10829,6 @@ double nonLinearMechSolver::solveSNL()
       // write the stress*.msh and disp*.msh files to check
       // loaded values
       /*
-      Msg::Info("Write stress and disp file after loading internal state");
       double DT = _timeManager->getTimeStep();
       double CURtime = DT+_timeManager->getLastTime();
       int NStep = _timeManager->getLastIterationIndex();