adjusting the tolerance

srcs/FEM/solverFEM.cpp

@@ -190,7 +190,7 @@ void solverFEMnonLinear(std::map<int, double> &electrostaticPressure,
         previousTotalNodalForces[i] = 0;
         currentTotalNodalForces[i] = 0;
     }
-    double residualTolerance = 1e-12; // empirical
+    double residualTolerance = 1e-10; // empirical
 
     double start5 = omp_get_wtime();
     step_name = "further initialization of global variables for the iterative algorithm";