def test_multiplier_exact(self):
c1 = Cell(content=Supported(3))
c2 = Cell(content=Supported(4))
c3 = Cell()
multiplier(c1, c2, c3)
scheduler.run()
self.assertEqual(c3.content, Supported(12))
def test_multiplier_interval(self):
c1 = Cell(content=Supported(Interval(3, 4)))
c2 = Cell(content=Supported(Interval(5, 6)))
c3 = Cell()
multiplier(c1, c2, c3)
scheduler.run()
self.assertEqual(c3.content, Supported(Interval(15, 24)))
def test_add_existing_neighbor(self):
f = lambda x: x
a = Cell(content='hello')
a.new_neighbor(f)
a.new_neighbor(f)
self.assertEqual(len(a.neighbors), 1)
def test_add_existing_neighbor(self):
f = lambda x: x
a = Cell(content='hello')
a.new_neighbor(f)
a.new_neighbor(f)
self.assertEqual(len(a.neighbors), 1)
def helper():
x_over_g = Cell('x/g')
g_plus_x_over_g = Cell('g+x/g')
two = Cell('two')
divider(x, g, x_over_g)
adder(g, x_over_g, g_plus_x_over_g)
(constant(2))(two)
divider(g_plus_x_over_g, two, h)
def to_do():
g_to_2 = Cell('g^2')
x_minus_g_to_2 = Cell('x-g^2')
ax_minus_g_to_2 = Cell('abs(x-g^2)')
multiplier(g, g, g_to_2)
subtractor(x, g_to_2, x_minus_g_to_2)
absolute_value(x_minus_g_to_2, ax_minus_g_to_2)
less_than(ax_minus_g_to_2, eps, done)
def test_false_to_true(self):
a = Cell(content=False)
b = Cell()
inverter(a, b)
scheduler.run()
self.assertEqual(b.content, True)
def test_false(self):
a = Cell(content=False)
b = Cell(content='yes')
c = Cell()
switch(a, b, c)
scheduler.run()
self.assertEqual(c.content, None)
def test_true(self):
a = Cell(content=True)
b = Cell(content='yes')
c = Cell()
switch(a, b, c)
scheduler.run()
self.assertEqual(c.content, 'yes')
def new_propagator_appends_function_to_neighbors(self):
a = Cell()
b = Cell()
c = Cell()
f = lambda x: x
Propagator([a, b, c], f)
for cell in [a, b, c]:
self.assertEqual(cell.neighbors, [f])
def test_integer_false(self):
a = Cell(content=13)
b = Cell(content=15)
c = Cell()
greater_than(a, b, c)
scheduler.run()
self.assertEqual(c.content, False)
def test_integer_true(self):
a = Cell(content=17)
b = Cell(content=15)
c = Cell()
greater_than(a, b, c)
scheduler.run()
self.assertEqual(c.content, True)
def fall_duration_helper():
g = Cell('g')
one_half = Cell('one half')
t_to_2 = Cell('t^2')
g_times_t_to_2 = Cell('gt^2')
(constant(Interval(9.789, 9.832)))(g)
(constant(Interval(0.5, 0.5)))(one_half)
quadratic(t, t_to_2)
product(g, t_to_2, g_times_t_to_2)
product(one_half, g_times_t_to_2, h)
def fall_duration_helper():
g = Cell('g')
one_half = Cell('one half')
t_to_2 = Cell('t^2')
g_times_t_to_2 = Cell('gt^2')
(constant(Interval(9.789, 9.832)))(g)
(constant(Interval(1 / 2, 1 / 2)))(one_half)
squarer(t, t_to_2)
multiplier(g, t_to_2, g_times_t_to_2)
multiplier(one_half, g_times_t_to_2, h)
def test_integer(self):
a = Cell()
b = Cell()
c = Cell()
multiplier(a, b, c)
a.add_content(5)
b.add_content(3)
scheduler.run()
self.assertEqual(c.content, 15)
def test_float(self):
a = Cell()
b = Cell()
c = Cell()
adder(a, b, c)
a.add_content(1.5)
b.add_content(1.3)
scheduler.run()
self.assertEqual(c.content, 2.8)
def test_str(self):
a = Cell()
b = Cell()
c = Cell()
adder(a, b, c)
a.add_content('15')
b.add_content('13')
scheduler.run()
self.assertEqual(c.content, '1513')
def test_integer(self):
a = Cell()
b = Cell()
c = Cell()
subtractor(a, b, c)
a.add_content(15)
b.add_content(13)
scheduler.run()
self.assertEqual(c.content, 2)
def test_integer(self):
a = Cell()
b = Cell()
c = Cell()
divider(a, b, c)
a.add_content(9)
b.add_content(3)
scheduler.run()
self.assertEqual(c.content, 3)
def test_integer(self):
a = Cell()
constant(5)(a)
scheduler.run()
self.assertEqual(a.content, 5)
def test_integer(self):
a = Cell()
b = Cell()
a_ = Cell()
b_ = Cell()
absolute_value(a, b)
absolute_value(a_, b_)
a.add_content(-9)
a_.add_content(9)
scheduler.run()
self.assertEqual(b.content, 9)
self.assertEqual(b_.content, 9)
def sqrt_iter_helper():
debug("sqrt_iter_helper: {x}, {g}, {answer}".format(**vars()))
done = Cell('done')
not_done = Cell('not(done)')
x_if_not_done = Cell('x if not(done)')
g_if_not_done = Cell('g if not(done)')
new_g = Cell('new g')
good_enuf(g, x, done)
switch(done, g, answer)
inverter(done, not_done)
switch(not_done, x, x_if_not_done)
switch(not_done, g, g_if_not_done)
heron_step(x_if_not_done, g_if_not_done, new_g)
# Clever recursion: this will call this helper again only if
# `x_if_not_done` is not None.
#
# `x_if_not_done` will not have content if `answer` has content,
# so it will stop recursing when an answer is found.
sqrt_iter(x_if_not_done, new_g, answer)
def test_integer(self):
a = Cell()
b = Cell()
c = Cell()
divider(a, b, c)
a.add_content(9)
b.add_content(3)
scheduler.run()
self.assertEqual(c.content, 3)
def test_float(self):
a = Cell()
b = Cell()
c = Cell()
adder(a, b, c)
a.add_content(1.5)
b.add_content(1.3)
scheduler.run()
self.assertEqual(c.content, 2.8)
def test_integer(self):
a = Cell()
b = Cell()
c = Cell()
subtractor(a, b, c)
a.add_content(15)
b.add_content(13)
scheduler.run()
self.assertEqual(c.content, 2)
def test_str(self):
a = Cell()
b = Cell()
c = Cell()
adder(a, b, c)
a.add_content('15')
b.add_content('13')
scheduler.run()
self.assertEqual(c.content, '1513')
def test_integer(self):
a = Cell()
b = Cell()
c = Cell()
multiplier(a, b, c)
a.add_content(5)
b.add_content(3)
scheduler.run()
self.assertEqual(c.content, 15)
def test_integer(self):
a = Cell()
b = Cell()
a_ = Cell()
b_ = Cell()
absolute_value(a, b)
absolute_value(a_, b_)
a.add_content(-9)
a_.add_content(9)
scheduler.run()
self.assertEqual(b.content, 9)
self.assertEqual(b_.content, 9)
def test_add_content_to_empty_cell(self):
a = Cell()
a.add_content('hello')
self.assertEqual(a.content, 'hello')
defined in this module.
"""
def good_enuf(g, x, done):
@compound(neighbors=[g, x])
def to_do():
g_to_2 = Cell('g^2')
x_minus_g_to_2 = Cell('x-g^2')
ax_minus_g_to_2 = Cell('abs(x-g^2)')
multiplier(g, g, g_to_2)
subtractor(x, g_to_2, x_minus_g_to_2)
absolute_value(x_minus_g_to_2, ax_minus_g_to_2)
less_than(ax_minus_g_to_2, eps, done)
return to_do
if __name__ == '__main__':
scheduler.initialize()
x = Cell('x')
answer = Cell('answer')
sqrt_network(x, answer)
x.add_content(2)
scheduler.run()
print(answer.content)
def test_new_cell_with_content(self):
a = Cell(content='hello')
b = Cell()
b.add_content('hello')
self.assertEqual(a.content, 'hello')
self.assertEqual(b.content, 'hello')
def similar_triangles_helper():
ratio = Cell('ratio')
product(s_ba, ratio, h_ba)
product(s, ratio, h)
product(one_half, g_times_t_to_2, h)
return fall_duration_helper
if __name__ == '__main__':
scheduler.initialize()
# We now build a sequence of sample dependency tracking systems of
# increasing complexity. We start with a relatively simple system
# that only tracks and reports the provenance of its data.
#
# How do we want our provenance system to work? We can make cells
# and define networks as usual, but if we add supported values as inputs,
# we get supported values as outputs:
barometer_height = Cell('barometer height')
barometer_shadow = Cell('barometer shadow')
building_height = Cell('building height')
building_shadow = Cell('building shadow')
similar_triangles(barometer_shadow, barometer_height, building_shadow, building_height)
building_shadow.add_content(Supported(Interval(54.9, 55.1), ['shadows']))
barometer_height.add_content(Supported(Interval(0.3, 0.32), ['shadows']))
barometer_shadow.add_content(Supported(Interval(0.36, 0.37), ['shadows']))
scheduler.run()
print(building_height.content)
# Supported(Interval(44.51351351351351, 48.977777777777774), {'shadows'})
def test_add_same_content_to_filled_cell(self):
a = Cell(content='hello')
a.add_content('hello')
self.assertEqual(a.content, 'hello')
def switch(predicate, if_true, output):
return conditional(predicate, if_true, Cell('_'), output)
def similar_triangles(s_ba, h_ba, s, h):
@compound(neighbors=[s_ba, h_ba, s])
def similar_triangles_helper():
ratio = Cell('ratio')
product(s_ba, ratio, h_ba)
product(s, ratio, h)
return similar_triangles_helper
if __name__ == '__main__':
scheduler.initialize()
# Now the estimation of the building’s height works just fine,
barometer_height = Cell('barometer height')
barometer_shadow = Cell('barometer shadow')
building_height = Cell('building height')
building_shadow = Cell('building shadow')
similar_triangles(barometer_shadow, barometer_height, building_shadow, building_height)
building_shadow.add_content(Interval(54.9, 55.1))
barometer_height.add_content(Interval(0.3, 0.32))
barometer_shadow.add_content(Interval(0.36, 0.37))
scheduler.run()
print(building_height.content)
# Interval(44.51351351351351, 48.977777777777774)
def test_add_new_content_to_filled_cell_returns_contradiction(self):
a = Cell(content='hello')
a.add_content('world')
self.assertTrue(is_contradictory(a.content))
def sqrt_network_helper():
one = Cell('one')
(constant(1))(one)
sqrt_iter(x, one, answer)
def test_add_same_content_to_filled_cell(self):
a = Cell(content='hello')
a.add_content('hello')
self.assertEqual(a.content, 'hello')
def test_new_cell_with_neighbors(self):
f = lambda x: x
a = Cell(content='hello')
a.new_neighbor(f)
self.assertEqual(a.neighbors, [f])
# `x_if_not_done` is not None.
#
# `x_if_not_done` will not have content if `answer` has content,
# so it will stop recursing when an answer is found.
sqrt_iter(x_if_not_done, new_g, answer)
return sqrt_iter_helper
"""
A `Cell` object containing a very small number.
Used in `good_enuf`.
"""
eps = Cell('eps', content=0.0000000001)
"""
Creates a propagator network that stores `True` in `done` if `g` is good
enough as a guess of the square root of `x`, and stores `False`
otherwise.
To be good enough, `g` and `x` contents have to obey this equation:
abs(x - pow(g, 2)) <= eps
Where `eps` is a `Cell` object containing a very small number, and is
defined in this module.
"""
def good_enuf(g, x, done):
def test_add_nothing_to_empty_cell(self):
a = Cell()
a.add_content(None)
self.assertEqual(a.content, None)
def similar_triangles(s_ba, h_ba, s, h):
@compound(neighbors=[s_ba, h_ba, s])
def similar_triangles_helper():
ratio = Cell('ratio')
product(s_ba, ratio, h_ba)
product(s, ratio, h)
return similar_triangles_helper
if __name__ == '__main__':
scheduler.initialize()
# Now the estimation of the building’s height works just fine,
barometer_height = Cell('barometer height')
barometer_shadow = Cell('barometer shadow')
building_height = Cell('building height')
building_shadow = Cell('building shadow')
similar_triangles(barometer_shadow, barometer_height, building_shadow,
building_height)
building_shadow.add_content(Interval(54.9, 55.1))
barometer_height.add_content(Interval(0.3, 0.32))
barometer_shadow.add_content(Interval(0.36, 0.37))
scheduler.run()
print(building_height.content)
# Interval(44.51351351351351, 48.977777777777774)
def test_new_cell_with_neighbors(self):
f = lambda x: x
a = Cell(content='hello')
a.new_neighbor(f)
self.assertEqual(a.neighbors, [f])
def test_new_cell_has_no_neighbors(self):
a = Cell(content='hello')
self.assertEqual(a.neighbors, [])
