def halver(function, x_0, initial_step=None, epsilon=None, max_iterations=100):
"""
Halving the interval, evaluate *function* based on *param*. Use
*initial_step*, *epsilon* precision and *max_iterations*.
"""
if initial_step is None:
# Figure out the step based on x_0 units (take one in the given unit)
step = q.Quantity(1, x_0.units)
else:
step = initial_step
if epsilon is None:
epsilon = q.Quantity(1e-4, x_0.units)
direction = 1
i = 0
last_x = x_0
y_0 = function(x_0)
# Remember the best x and y
best = x_0, y_0
def turn(direction, step):
"""Turn to opposite direction and reduce the step by half."""
return -direction, step / 2.0
def move(x_0, direction, step):
"""Move to a *direction* by a *step*."""
return x_0 + direction * step
x_0 = move(x_0, direction, step)
while i < max_iterations:
y_1 = function(x_0)
if step < epsilon:
break
if y_1 >= y_0:
# Worse, change direction and move to the half of the last
# good x and the new x.
direction, step = turn(direction, step)
x_0 = (x_0 + last_x) / 2
else:
# OK, move forward.
if y_1 < best[1]:
# The new y is better then the so far obtained one
best = x_0, y_1
last_x = x_0
x_0 = move(x_0, direction, step)
y_0 = y_1
i += 1
# Apply the best known value
function(best[0])
return best[0]
def q_func(x):
"""We need to run the objective function in a separate thread and loop because we
have been called from a running event loop and have things to do in an event loop
and can't use the running one.
"""
coro = eval_func(q.Quantity(strip_func(x), x_0.units))
return run_in_loop_thread_blocking(coro)
async def _wrapper(instance):
value = instance.uca.get_property(name)
if unit:
return q.Quantity(value, unit)
return value
def _vectorize(scalar, coordinate):
"""
Return a vector with the *scalar* in the correct place given by the
*coordinate* as x, y or z.
"""
vector = np.zeros(3, dtype=np.float)
translate = dict(x=0, y=1, z=2)
vector[translate[coordinate]] = scalar.magnitude
return q.Quantity(vector, scalar.units)
def test_degree_conversion(self):
from concert.devices.cameras.uca import Camera
camera = Camera("mock")
camera.degree_value = q.Quantity(5, q.celsius)
self.assertEqual(camera.degree_value.magnitude, 5.0)
val = camera.degree_value.magnitude
camera.degree_value = camera.degree_value + 5 * q.delta_degC
self.assertEqual(camera.degree_value.magnitude, val + 5)
def _get_weight(self):
"""
Get weight from the scales. The command does not return until
a balanced position is found, thus it can time out.
"""
res = self._connection.execute("P")
if "Err8.4" in res:
self._set_state(ARRW60.ERROR)
raise WeightError("More than maximum weight loaded")
else:
if self.state == ARRW60.ERROR or self.state == Device.NA:
# Clear the error from before or set OK for the first time
self._set_state(ARRW60.OK)
# The returned string contains units
res = q.Quantity(res).to(q.g)
return float(res.magnitude) * q.counts
async def wrapper(eval_func, x_0, *args, **kwargs):
def q_func(x):
"""We need to run the objective function in a separate thread and loop because we
have been called from a running event loop and have things to do in an event loop
and can't use the running one.
"""
coro = eval_func(q.Quantity(strip_func(x), x_0.units))
return run_in_loop_thread_blocking(coro)
def to_run_in_exec():
"""Run the optimization *function* in a pool so that we comply with the async nature
of concert.
"""
return function(q_func, x_0.magnitude, *args, **kwargs)
dim_less = await run_in_executor(to_run_in_exec)
return q.Quantity(dim_less, x_0.units)
def wrapper(eval_func, x_0, *args, **kwargs):
q_func = lambda x: eval_func(q.Quantity(strip_func(x), x_0.units))
dim_less = function(q_func, x_0.magnitude, *args, **kwargs)
return q.Quantity(dim_less, x_0.units)
