discretize.TreeMesh.project_node_to_boundary_node

TreeMesh.project_node_to_boundary_node

Projection matrix from all nodes to boundary nodes.

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

ub = P @ u

Returns:

(n_boundary_nodes, n_nodes) scipy.sparse.csr_matrix

Projection matrix with shape