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Improve clifford.py, add measurement lookup table

master
Pete Shadbolt 8 years ago
parent
commit
092afb82f6
3 changed files with 49 additions and 55 deletions
  1. +45
    -43
      abp/clifford.py
  2. +2
    -6
      tests/test_against_anders_and_briegel.py
  3. +2
    -6
      tests/test_measurement.py

+ 45
- 43
abp/clifford.py View File

@@ -17,15 +17,12 @@ decompositions = ("xxxx", "xx", "zzxx", "zz", "zxx", "z", "zzz", "xxz",

def conjugate(vop, transform):
""" Returns transform * vop * transform^dagger and a phase in {+1, -1} """
assert vop in set(xrange(4))
op = times_table[transform, vop]
op = times_table[op, conjugation_table[transform]]
is_id_or_vop = (transform % 4 == 0) or (transform % 4 == vop)
is_non_pauli = (transform >= 4) and (transform <= 15)
phase = ((-1, 1), (1, -1))[is_id_or_vop][is_non_pauli]
if vop == 0:
phase = 1
return op, phase
return measurement_table[vop, transform]

def use_old_cz():
""" Use the CZ table from A&B's code """
global cz_table
from anders_cz import cz_table

def get_name(i):
@@ -109,7 +106,8 @@ def get_measurement_table():
Compute a table of transform * operation * transform^dagger
This is pretty unintelligible right now, we should probably compute the phase from unitaries instead
"""
for operation_index, transform_index in itertools.product(range(4), range(24)):
measurement_table = np.zeros((4, 24, 2), dtype=complex)
for vop, transform in it.product(range(4), range(24)):
assert vop in set(xrange(4))
op = times_table[transform, vop]
op = times_table[op, conjugation_table[transform]]
@@ -118,9 +116,8 @@ def get_measurement_table():
phase = ((-1, 1), (1, -1))[is_id_or_vop][is_non_pauli]
if vop == 0:
phase = 1
return op, phase

measurement_table[vop, transform] = [op, phase]
return measurement_table


def get_commuters(unitaries):
@@ -166,47 +163,52 @@ def write_javascript_tables():
.format(json.dumps(by_name)))
f.write("};");

def temp(filename):
""" Get a temporary path """
tempdir = tempfile.gettempdir()
return os.path.join(tempdir, filename)

# First try to load tables from cache. If that fails, build them from
# scratch and store in /tmp/
tempdir = tempfile.gettempdir()
temp = lambda filename: os.path.join(tempdir, filename)
try:
if __name__ == "__main__":
raise IOError

# Parse command line args
# parser = argparse.ArgumentParser()
# parser.add_argument("-l", "--legacy", help="Use legacy CZ table", action="store_true", default=False)
# args = parser.parse_args()
legacy_cz = False

unitaries = np.load(temp("unitaries.npy"))
conjugation_table = np.load(temp("conjugation_table.npy"))
times_table = np.load(temp("times_table.npy"))
if legacy_cz:
import anders_cz
cz_table = anders_cz.cz_table
else:
cz_table = np.load(temp("cz_table.npy"))

with open(temp("by_name.json")) as f:
by_name = json.load(f)

except IOError:
# Spend time building the tables
def compute_everything():
""" Compute all lookup tables """
global unitaries, by_name, conjugation_table, times_table, cz_table, measurement_table
unitaries = get_unitaries()
by_name = get_by_name(unitaries)
conjugation_table = get_conjugation_table(unitaries)
times_table = get_times_table(unitaries)
cz_table = get_cz_table(unitaries)
measurement_table = get_measurement_table()

# Write it all to disk
def save_to_disk():
""" Save all tables to disk """
global unitaries, by_name, conjugation_table, times_table, cz_table, measurement_table
np.save(temp("unitaries.npy"), unitaries)
np.save(temp("conjugation_table.npy"), conjugation_table)
np.save(temp("times_table.npy"), times_table)
np.save(temp("cz_table.npy"), cz_table)
np.save(temp("measurement_table.npy"), measurement_table)
write_javascript_tables()

with open(temp("by_name.json"), "wb") as f:
json.dump(by_name, f)

def load_from_disk():
""" Load all the tables from disk """
global unitaries, by_name, conjugation_table, times_table, cz_table, measurement_table
unitaries = np.load(temp("unitaries.npy"))
conjugation_table = np.load(temp("conjugation_table.npy"))
times_table = np.load(temp("times_table.npy"))
measurement_table = np.load(temp("measurement_table.npy"))
cz_table = np.load(temp("cz_table.npy"))

with open(temp("by_name.json")) as f:
by_name = json.load(f)


if __name__ == "__main__":
compute_everything()
save_to_disk()
else:
try:
load_from_disk()
except IOError:
compute_everything()
save_to_disk()

+ 2
- 6
tests/test_against_anders_and_briegel.py View File

@@ -48,9 +48,7 @@ def test_local_rotations():
def test_cz_table(N=10):
""" Test the CZ table """

# Don't test if we are using Pete's CZ table - doesn't make sense
if not clifford.legacy_cz:
return
clifford.use_old_cz()

for j in range(24):
a = graphsim.GraphRegister(2)
@@ -92,9 +90,7 @@ def test_with_cphase_gates_hadamard_only(N=10):
def test_all(N=10):
""" Test all gates at random """

# Don't test if we are using Pete's CZ table - doesn't make sense
if not clifford.legacy_cz:
return
clifford.use_old_cz()

a = graphsim.GraphRegister(N)
b = GraphState()


+ 2
- 6
tests/test_measurement.py View File

@@ -1,14 +1,10 @@
from abp import GraphState

def test_z_measurement():
g = GraphState(0)
g = GraphState([0])
assert g.measure_z(0, 0) == 0
assert g.measure_z(0, 1) == 1
assert not all(g.measure_z(0) == 0 for i in range(100))

g.act_hadamard(0)
print g
assert all(g.measure_z(0) == 1 for i in range(100))
# TODO




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