discretize.base.BaseRectangularMesh.project_face_to_boundary_face

property BaseRectangularMesh.project_face_to_boundary_face

Projection matrix from all faces to boundary faces.

Constructs and returns a matrix \(\mathbf{P}\) that projects from all mesh faces to boundary faces. That is, for a discrete vector \(\mathbf{u}\) that lives on the faces, the values on the boundary faces \(\mathbf{u_b}\) can be extracted via the following matrix-vector product:

ub = P @ u

Returns:

scipy.sparse.csr_matrix

(n_boundary_faces, n_faces) Projection matrix with shape