def test_e03():
""" Minimal test of low-energy spectrum search. """
# expected number of states with dE<1 for droplet instance 1 for L=128
expected_number_of_states = 31
ins0 = search_spectrum_droplet(D=16, excitations_encoding=1, rot=0, precondition=False, dE=1.)
ins1 = search_spectrum_droplet(D=16, excitations_encoding=1, rot=1, precondition=False, dE=1.)
ins2 = search_spectrum_droplet(D=16, excitations_encoding=2, rot=2, precondition=False, dE=1.)
ins3 = search_spectrum_droplet(D=16, excitations_encoding=3, rot=3, precondition=False, dE=1.)
ins0.decode_low_energy_states(max_dEng=1.)
ins1.decode_low_energy_states(max_dEng=1.)
ins2.decode_low_energy_states(max_dEng=1.)
ins3.decode_low_energy_states(max_dEng=1.)
assert(len(ins0.energy) == expected_number_of_states)
assert(len(ins1.energy) == expected_number_of_states)
assert(len(ins2.energy) == expected_number_of_states)
assert(len(ins3.energy) == expected_number_of_states)
err0 = max(abs(ins0.energy - ins1.energy))
err1 = max(abs(ins1.energy - ins2.energy))
err2 = max(abs(ins1.energy - ins3.energy))
assert(max(err0, err1, err2) < 1e-4)
st0 = ins0.binary_states()
st1 = ins1.binary_states()
st2 = ins2.binary_states()
st3 = ins3.binary_states()
filename_in = os.path.join(os.path.dirname(__file__),
'./../instances/Chimera_droplet_instances/chimera128_spinglass_power/001.txt')
J = tnac4o.load_Jij(filename_in)
J = tnac4o.Jij_f2p(J)
J = tnac4o.round_Jij(J, 1 / 75)
E0 = tnac4o.energy_Jij(J, st0)
E1 = tnac4o.energy_Jij(J, st1)
E2 = tnac4o.energy_Jij(J, st2)
E3 = tnac4o.energy_Jij(J, st3)
err0 = max(abs(E1 - E0))
err1 = max(abs(E2 - E0))
err2 = max(abs(E3 - E0))
assert(max(err0, err1, err2) < 1e-4)
def test_e02():
""" Minimal test of Gibbs sampling. """
M = 128
ins0 = gibbs_sampling(M=M, precondition=False, rot=0)
assert(M == len(ins0.states))
ins1 = gibbs_sampling(M=M, precondition=False, rot=1)
filename_in = os.path.join(os.path.dirname(__file__),
'./../instances/Chimera_droplet_instances/chimera128_spinglass_power/001.txt')
# test consistency of energies
J = tnac4o.load_Jij(filename_in)
J = tnac4o.Jij_f2p(J)
J = tnac4o.round_Jij(J, 1 / 75)
st0 = ins0.binary_states()
st1 = ins1.binary_states()
E0 = tnac4o.energy_Jij(J, st0)
E1 = tnac4o.energy_Jij(J, st1)
err0 = max(abs(ins0.energy - E0))
err1 = max(abs(ins1.energy - E1))
assert(max(err0, err1) < 1e-6)
def search_gs_droplet(L=128,
instance=1,
rot=0,
beta=3,
D=48,
M=1024,
relative_P_cutoff=1e-8,
precondition=True):
'''
Runs a script searching for a ground state of a droplet instance.
Instances are located in the folder ./../instances/.
Reasonable (but not neccesarily optimal) values of parameters for those instances are set as default.
Some can be changed using options in this script. See documentation for more information.
'''
# Initialize global logging level to INFO.
logging.basicConfig(level='INFO')
# filename of the instance of interest
if L == 128:
Nx, Ny, Nc = 4, 4, 8
filename_in = os.path.join(
os.path.dirname(__file__),
'./../instances/Chimera_droplet_instances/chimera128_spinglass_power/%03d.txt'
% instance)
elif L == 512:
Nx, Ny, Nc = 8, 8, 8
filename_in = os.path.join(
os.path.dirname(__file__),
'./../instances/Chimera_droplet_instances/chimera512_spinglass_power/%03d.txt'
% instance)
elif L == 1152:
Nx, Ny, Nc = 12, 12, 8
filename_in = os.path.join(
os.path.dirname(__file__),
'./../instances/Chimera_droplet_instances/chimera1152_spinglass_power/%03d.txt'
% instance)
elif L == 2048:
Nx, Ny, Nc = 16, 16, 8
filename_in = os.path.join(
os.path.dirname(__file__),
'./../instances/Chimera_droplet_instances/chimera2048_spinglass_power/%03d.txt'
% instance)
# load Jij couplings
J = tnac4o.load_Jij(filename_in)
# those instances are defined with spin numering starting with 1
# change to 0-base indexing
J = tnac4o.Jij_f2p(J)
# round J to multiplies of 1/75 for those instances
# as couplings were saved with 6 digit precision
J = tnac4o.round_Jij(J, 1 / 75)
# initializes solver
ins = tnac4o.tnac4o(mode='Ising', Nx=Nx, Ny=Ny, Nc=Nc, J=J, beta=beta)
ins.logger.info(
'Analysing droplet instance %1d on chimera graph of %1d sites.' %
(instance, L))
# rotates graph to contract from different side/edge
if rot > 0:
ins.rotate_graph(rot=rot)
# applies preconditioning using balancing heuristics
if precondition:
ins.precondition(mode='balancing')
# search ground state (return lowest energy, full data stored in ins)
Eng = ins.search_ground_state(M=M,
relative_P_cutoff=relative_P_cutoff,
Dmax=D)
return ins
def main():
"""
Runs a script loading solution for low energy spectrum, and decoding it.
Instances are located in the folder ./../instances/.
Reasonable (but not neccesarily optimal) values of parameters for those instances are set as default.
Some can be changed using options in this script. See documentation for more information.
"""
# Initialize global logging level to INFO.
parser = argparse.ArgumentParser()
parser.add_argument("-L",
type=int,
choices=[128, 512, 1152, 2048],
default=128,
help="Size of chimera graph. Default is 128 (C4).")
parser.add_argument("-ins",
type=int,
choices=range(1, 101),
metavar="[1-100]",
default=1,
help="Instance number (1-100). Default is 1.")
parser.add_argument("-r",
type=int,
default=0,
help="Rotate graph by 90 deg r times. Default is 0. \
Used to try to search/contract from different sides."
)
parser.add_argument("-b",
type=float,
default=3,
help="Inverse temperature. Default is set at 3.")
parser.add_argument(
"-D",
type=int,
default=48,
help="Maximal bond dimension of boundary MPS used to contract PEPS.")
parser.add_argument(
"-M",
type=int,
default=2**10,
help=
"Maximal number of partial states kept during branch and bound search."
)
parser.add_argument(
"-P",
type=float,
default=1e-8,
help=
"Cuttof on the range of relative probabilities kept during branch and bound search."
)
parser.add_argument("-dE",
type=float,
default=1.0,
help="Limit on excitation energy.")
parser.add_argument(
"-hd",
type=int,
default=0,
help=
"Lower limit of Hamming distance between states (while merging). Outputs less states."
)
parser.add_argument(
"-max_st",
type=int,
default=2**20,
help=
"Limit total number of low energy states which is being reconstructed."
)
parser.add_argument("-ee",
type=int,
default=1,
choices=[1, 2, 3],
help="Strategy used to compress droplets. \
For excitations_encoding = 2 or 3 small noise is added to the couplings slighly modyfings energies."
)
parser.add_argument('-no-pre',
dest='pre',
action='store_false',
help="Do not use preconditioning.")
parser.set_defaults(pre=True)
args = parser.parse_args()
if args.L == 128:
Nx, Ny, Nc = 4, 4, 8
filename_in = os.path.join(
os.path.dirname(__file__),
'./../instances/Chimera_droplet_instances/chimera128_spinglass_power/%03d.txt'
% args.ins)
elif args.L == 512:
Nx, Ny, Nc = 8, 8, 8
filename_in = os.path.join(
os.path.dirname(__file__),
'./../instances/Chimera_droplet_instances/chimera512_spinglass_power/%03d.txt'
% args.ins)
elif args.L == 1152:
Nx, Ny, Nc = 12, 12, 8
filename_in = os.path.join(
os.path.dirname(__file__),
'./../instances/Chimera_droplet_instances/chimera1152_spinglass_power/%03d.txt'
% args.ins)
elif args.L == 2048:
Nx, Ny, Nc = 16, 16, 8
filename_in = os.path.join(
os.path.dirname(__file__),
'./../instances/Chimera_droplet_instances/chimera2048_spinglass_power/%03d.txt'
% args.ins)
# load Jij couplings
J = tnac4o.load_Jij(filename_in)
# those instances are defined with spin numering starting with 1
# change to 0-base indexing
J = tnac4o.Jij_f2p(J)
# round J to multiplies of 1/75 for those instances
# as couplings were saved with 6 digit precision
J = tnac4o.round_Jij(J, 1 / 75)
logging.basicConfig(level='INFO')
# file to load
file_name = os.path.join(
os.path.dirname(__file__),
'./results/L=%1d_ins=%03d_r=%1d_beta=%0.2f_D=%1d_M=%1d_P=%0.2e_ee=%1d_dE=%0.3f_hd=%1d_pre=%1d.npy'
% (args.L, args.ins, args.r, args.b, args.D, args.M, args.P, args.ee,
args.dE, args.hd, args.pre))
# load instance
try:
ins = tnac4o.load(file_name)
except FileNotFoundError:
raise Exception(
'First run script e03_search_spectrum_droplet_instances.py with option `-s`'
)
print('Decomposing excitation structure into low energy states.')
keep_time_decode = time.time()
Eng = ins.decode_low_energy_states(max_dEng=args.dE,
max_states=args.max_st)
bit_strings = ins.binary_states()
ins.logger.info('Decoding spectrum elapse time : %.2f seconds',
time.time() - keep_time_decode)
ins.show_solution()
Eng = tnac4o.energy_Jij(J, bit_strings)
error = max(abs(ins.energy - Eng))
print('Consistency of different ways to calculate energies.')
print('For ee = 2 or 3 expected difference is ~1e-6 due to applied noise.')
print('Difference = ', error)
return error
def search_spectrum_droplet(L=128,
instance=1,
rot=0,
beta=3,
D=48,
M=1024,
relative_P_cutoff=1e-8,
excitations_encoding=1,
dE=1.,
hd=0,
precondition=True):
"""
Runs a script searching for ground state of `droplet instances`.
Instances are located in the folder ./../instances/.
Reasonable (but not neccesarily optimal) values of parameters for those instances are set as default.
Some can be changed using options in this script. See documentation for more information.
"""
# Initialize global logging level to INFO.
logging.basicConfig(level='INFO')
# filename of the instance of interest
if L == 128:
Nx, Ny, Nc = 4, 4, 8
filename_in = os.path.join(
os.path.dirname(__file__),
'./../instances/Chimera_droplet_instances/chimera128_spinglass_power/%03d.txt'
% instance)
elif L == 512:
Nx, Ny, Nc = 8, 8, 8
filename_in = os.path.join(
os.path.dirname(__file__),
'./../instances/Chimera_droplet_instances/chimera512_spinglass_power/%03d.txt'
% instance)
elif L == 1152:
Nx, Ny, Nc = 12, 12, 8
filename_in = os.path.join(
os.path.dirname(__file__),
'./../instances/Chimera_droplet_instances/chimera1152_spinglass_power/%03d.txt'
% instance)
elif L == 2048:
Nx, Ny, Nc = 16, 16, 8
filename_in = os.path.join(
os.path.dirname(__file__),
'./../instances/Chimera_droplet_instances/chimera2048_spinglass_power/%03d.txt'
% instance)
# load Jij couplings
J = tnac4o.load_Jij(filename_in)
# those instances are defined with spin numering starting with 1
# change to 0-base indexing
J = tnac4o.Jij_f2p(J)
# round J to multiplies of 1/75 for those instances
# as couplings were saved with 6 digit precision
J = tnac4o.round_Jij(J, 1 / 75)
# initialize solver
ins = tnac4o.tnac4o(mode='Ising', Nx=Nx, Ny=Ny, Nc=Nc, J=J, beta=beta)
ins.logger.info(
'Analysing droplet instance %1d on chimera graph of %1d sites.' %
(instance, L))
# rotates graph
if rot > 0:
ins.rotate_graph(rot=rot)
# if using excitations_encoding = 2 or 3
# adds small noise to remove accidental degeneracies
if excitations_encoding > 1:
ins.add_noise(amplitude=1e-7)
# applies preconditioning using balancing heuristics
if precondition:
ins.precondition(mode='balancing')
# search for low energy spectrum (return lowest energy, full data stored in ins)
Eng = ins.search_low_energy_spectrum(
excitations_encoding=excitations_encoding,
M=M,
relative_P_cutoff=relative_P_cutoff,
Dmax=D,
max_dEng=dE,
lim_hd=hd)
return ins