Taking the Dirichlet boundary conditions into account

 


As the boundary conditions of first type are partialy taken into account during the computation of the stiffness matrix and right-hand side without boundary conditions and the computation of the boundary conditions of third type, there are now only two more things to do : to set the values on the diagonal of the stiffness matrix to "1" and the entries of the right-hand size corresponding to Dirichlet nodes to the value of the boundary conditions.

For each Dirichlet node, which has i as global number.

     Kii = 1
     fi = g1(xi);


g1(xi) is the value of the Dirichlet boundary condition at the point xi.