def force_update_from_form(force, form):
"""Update the force diagram after modifying the (force densities of) the form diagram.
Parameters
----------
force : :class:`ForceDiagram`
The force diagram on which the update is based.
form : :class:`FormDiagram`
The form diagram to update.
Returns
-------
force: :class:`ForceDiagram`
The updated force diagram.
"""
# --------------------------------------------------------------------------
# form diagram
# --------------------------------------------------------------------------
vertex_index = form.vertex_index()
xy = array(form.xy(), dtype=float64)
edges = [[vertex_index[u], vertex_index[v]] for u, v in form.edges_where({'_is_edge': True})]
C = connectivity_matrix(edges, 'csr')
Q = diags([form.q()], [0])
uv = C.dot(xy)
# --------------------------------------------------------------------------
# force diagram
# --------------------------------------------------------------------------
_vertex_index = force.vertex_index()
_known = [_vertex_index[force.anchor()]]
_xy = array(force.xy(), dtype=float64)
_edges = force.ordered_edges(form)
_edges[:] = [(_vertex_index[u], _vertex_index[v]) for u, v in _edges]
_C = connectivity_matrix(_edges, 'csr')
_Ct = _C.transpose()
# --------------------------------------------------------------------------
# compute reciprocal for given q
# --------------------------------------------------------------------------
_xy = spsolve_with_known(_Ct.dot(_C), _Ct.dot(Q).dot(uv), _xy, _known)
# --------------------------------------------------------------------------
# update force diagram
# --------------------------------------------------------------------------
for vertex, attr in force.vertices(True):
index = _vertex_index[vertex]
attr['x'] = _xy[index, 0]
attr['y'] = _xy[index, 1]
return force
def force_update_from_form(force, form):
"""Update the force diagram after modifying the (force densities of) the form diagram.
Parameters
----------
force : ForceDiagram
The force diagram on which the update is based.
form : FormDiagram
The form diagram to update.
Returns
-------
None
The form and force diagram are updated in-place.
"""
# --------------------------------------------------------------------------
# form diagram
# --------------------------------------------------------------------------
k_i = form.key_index()
xy = array(form.xy(), dtype=float64)
edges = [[k_i[u], k_i[v]] for u, v in form.edges()]
C = connectivity_matrix(edges, 'csr')
Q = diags([form.q()], [0])
uv = C.dot(xy)
# --------------------------------------------------------------------------
# force diagram
# --------------------------------------------------------------------------
_k_i = force.key_index()
_known = [_k_i[force.anchor()]]
_xy = array(force.xy(), dtype=float64)
_edges = force.ordered_edges(form)
_C = connectivity_matrix(_edges, 'csr')
_Ct = _C.transpose()
# --------------------------------------------------------------------------
# compute reciprocal for given q
# --------------------------------------------------------------------------
_xy = spsolve_with_known(_Ct.dot(_C), _Ct.dot(Q).dot(uv), _xy, _known)
# --------------------------------------------------------------------------
# update force diagram
# --------------------------------------------------------------------------
for key, attr in force.vertices(True):
i = _k_i[key]
attr['x'] = _xy[i, 0]
attr['y'] = _xy[i, 1]