Classes for making standard monitor functions

demos/monge_ampere_ring.py

@@ -73,21 +73,16 @@
 #
 # for some values of the parameters :math:`\alpha`, :math:`\beta`, and :math:`\gamma`.
 # Unity is added at the start to ensure that the monitor function doesn't get too
-# close to zero.
+# close to zero. Here we can think of :math:`\alpha` as relating to the amplitude of the
+# monitor function, :math:`\beta` as relating to the width of the ring, and
+# :math:`\gamma` as the radius of the ring.
 #
-# Here we can think of :math:`\alpha` as relating to the amplitude of the monitor
-# function, :math:`\beta` as relating to the width of the ring, and :math:`\gamma` as
-# the radius of the ring.
-
-
-def ring_monitor(mesh):
-    alpha = Constant(20.0)
-    beta = Constant(200.0)
-    gamma = Constant(0.15)
-    x, y = SpatialCoordinate(mesh)
-    r = (x - 0.5) ** 2 + (y - 0.5) ** 2
-    return Constant(1.0) + alpha / cosh(beta * (r - gamma)) ** 2
+# For convenience, Movement provides a builder class for ring monitors,
+# :class:`~movement.monitor.RingMonitorBuilder`, amongst other commonly used
+# monitor functions. ::
 
+mb = RingMonitorBuilder(centre=(0.5, 0.5), radius=0.4, amplitude=20.0, width=200.0)
+ring_monitor = mb.get_monitor()
 
 # With an initial mesh and a monitor function, we are able to construct a
 # :class:`~movement.monge_ampere.MongeAmpereMover` instance and adapt the mesh. By

movement/__init__.py

@@ -1,3 +1,4 @@
+from movement.monitor import *  # noqa
 from movement.tangling import *  # noqa
 
 from movement.laplacian_smoothing import *  # noqa