# Other “explicit” bricks¶

Two (very simple) bricks allow to add some explicit terms to the tangent system.

The function:

indbrick = getfem::add_explicit_matrix(md, varname1, varname2, B
issymmetric = false,
iscoercive = false);


adds a brick which just adds the matrix B to the tangent system relatively to the variables varname1 and varname2. The given matrix should have as many rows as the dimension of varname1 and as many columns as the dimension of varname2. If the two variables are different and if issymmetric is set to true then the transpose of the matrix is also added to the tangent system (default is false). Set iscoercive to true if the term does not affect the coercivity of the tangent system (default is false). The matrix can be changed by the command:

getfem::set_private_data_matrix(md, indbrick, B);


The function:

getfem::add_explicit_rhs(md, varname, L);


adds a brick which just add the vector L to the right hand side of the tangent system relatively to the variable varname. The given vector should have the same size as the variable varname. The value of the vector can by changed by the command:

getfem::set_private_data_rhs(md, indbrick, L);