def test_clamped_model_sample_multple(self):
"""
Test that clamped model sample with multiple clamped variables gets the
correct energy.
"""
checkerboard = IsingModel(
J={(0, 1): 1, (1, 2): 1, (2, 3): 1, (3, 0): 1},
h={}
)
checkerboard.clamp(1, 1)
checkerboard.clamp(3, -1)
sample = IsingSample(checkerboard, (-1, 1))
assert sample.assignment.as_tuple == (-1, 1, 1, -1)
assert sample.energy == 0
checkerboard = IsingModel(
J={(0, 1): 1, (1, 2): 1, (2, 3): 1, (3, 0): 1},
h={1: 4}
)
checkerboard.clamp(0, -1)
checkerboard.clamp(1, 1)
checkerboard.clamp(2, 1)
checkerboard.clamp(3, -1)
sample = IsingSample(checkerboard, tuple())
assert sample.assignment.as_tuple == (-1, 1, 1, -1)
assert sample.energy == 4
def test_clamp_variable_not_present(self):
"""
Make sure invalid variable cannot be clamped.
"""
h = {0: 4.5, 1: 10, 2: -5}
J = {(0, 1): -4.5, (1, 2): 5}
model = IsingModel(J, h)
with pytest.raises(ValueError):
model.clamp(8, 1)
def test_clamp_variable_already_clamped(self):
"""
Make sure invalid variable cannot be clamped.
"""
h = {0: 4.5, 1: 10, 2: -5}
J = {(0, 1): -4.5, (1, 2): 5}
model = IsingModel(J, h)
# Clamp the variable
model.clamp(2, -1)
# Attempt to clamp the variable again
with pytest.raises(ValueError):
model.clamp(2, 1)
def test_clamp_variable_simple(self):
"""
Makes sure that variable clamping transforms IsingModel in an expected manner.
"""
h = {0: 4.5, 1: 10, 2: -5}
J = {(0, 1): -4.5, (1, 2): 5}
model = IsingModel(J, h)
model.clamp(0, 1)
assert model.h_clamped == {1: 5.5, 2: -5}
assert model.J_clamped == {(1, 2): 5}
model = IsingModel(J, h)
model.clamp(0, -1)
assert model.h_clamped == {1: 14.5, 2: -5}
assert model.J_clamped == {(1, 2): 5}
def test_clamp_multiple_variables(self):
"""
Make sure clamping multiple variables work.
"""
h = {0: 4, 1: 10, 2: -5, 3: 4, 4: -5}
J = {(0, 1): -6, (1, 2): 5, (0, 3): 3, (0, 2): -4}
model = IsingModel(J, h)
model.clamp(0, -1)
model.clamp(2, 1)
model.clamp(4, -1)
assert model.h_clamped == {1: 21, 3: 1}
assert model.J_clamped == {}
def test_clamp_not_affecting_original(self):
"""
Make sure that the original ising model definition is not affected by
clamping variables.
"""
h = {0: 4, 1: 10, 2: -5, 3: 4, 4: -5}
J = {(0, 1): -6, (1, 2): 5, (0, 3): 3, (0, 2): -4}
model = IsingModel(J, h)
model.clamp(0, -1)
model.clamp(2, 1)
model.clamp(4, -1)
assert model.h == {0: 4, 1: 10, 2: -5, 3: 4, 4: -5}
assert model.J == {(0, 1): -6, (1, 2): 5, (0, 3): 3, (0, 2): -4}
def test_clamped_model_sample(self):
"""
Test that clamped model sample gets the correct energy.
"""
checkerboard = IsingModel(
J={(0, 1): 1, (1, 2): 1, (2, 3): 1, (3, 0): 1},
h={}
)
checkerboard.clamp(0, 1)
sample = IsingSample(checkerboard, (-1, 1, -1))
assert sample.assignment.as_tuple == (1, -1, 1, -1)
assert sample.assignment == {0: 1, 1: -1, 2: 1, 3: -1}
assert sample.energy == -4
checkerboard = IsingModel(
J={(0, 1): 1, (1, 2): 1, (2, 3): 1, (3, 0): 1},
h={0: 5}
)
checkerboard.clamp(0, 1)
sample = IsingSample(checkerboard, (-1, 1, -1))
assert sample.assignment.as_tuple == (1, -1, 1, -1)
assert sample.assignment == {0: 1, 1: -1, 2: 1, 3: -1}
assert sample.energy == 1
checkerboard = IsingModel(
J={(0, 1): 1, (1, 2): 1, (2, 3): 1, (3, 0): 1},
h={0: -3, 3: 2}
)
checkerboard.clamp(3, -1)
sample = IsingSample(checkerboard, (-1, -1, -1))
assert sample.assignment.as_tuple == (-1, -1, -1, -1)
assert sample.assignment == {0: -1, 1: -1, 2: -1, 3: -1}
assert sample.energy == 5
def test_clamp_variable_invalid_value(self):
"""
Make sure invalid variable cannot be clamped.
"""
h = {0: 4.5, 1: 10, 2: -5}
J = {(0, 1): -4.5, (1, 2): 5}
model = IsingModel(J, h)
# Attempt to clamp with some retarded value
with pytest.raises(ValueError):
model.clamp(2, 5)
with pytest.raises(ValueError):
model.clamp(2, -3)
with pytest.raises(ValueError):
model.clamp(2, 1.01)
with pytest.raises(ValueError):
model.clamp(2, -0.99)
with pytest.raises(ValueError):
model.clamp(2, 0)
with pytest.raises(ValueError):
model.clamp(2, -0.5)