def __grad_vector_objective(objective: typing.Union[Objective,
VectorObjective],
variable: Variable):
argsets = objective.argsets
transformations = objective._transformations
outputs = []
for pos in range(len(objective)):
args = argsets[pos]
transformation = transformations[pos]
dO = None
processed_expectationvalues = {}
for i, arg in enumerate(args):
if __AUTOGRAD__BACKEND__ == "jax":
df = jax.grad(transformation, argnums=i)
elif __AUTOGRAD__BACKEND__ == "autograd":
df = jax.grad(transformation, argnum=i)
else:
raise TequilaException(
"Can't differentiate without autograd or jax")
# We can detect one simple case where the outer derivative is const=1
if transformation is None or transformation == identity:
outer = 1.0
else:
outer = Objective(args=args, transformation=df)
if hasattr(arg, "U"):
# save redundancies
if arg in processed_expectationvalues:
inner = processed_expectationvalues[arg]
else:
inner = __grad_inner(arg=arg, variable=variable)
processed_expectationvalues[arg] = inner
else:
# this means this inner derivative is purely variable dependent
inner = __grad_inner(arg=arg, variable=variable)
if inner == 0.0:
# don't pile up zero expectationvalues
continue
if dO is None:
dO = outer * inner
else:
dO = dO + outer * inner
if dO is None:
dO = Objective()
outputs.append(dO)
if len(outputs) == 1:
return outputs[0]
return outputs
def __grad_objective(objective: Objective, variable: Variable):
args = objective.args
transformation = objective.transformation
dO = None
processed_expectationvalues = {}
for i, arg in enumerate(args):
if __AUTOGRAD__BACKEND__ == "jax":
df = jax.grad(transformation, argnums=i)
elif __AUTOGRAD__BACKEND__ == "autograd":
df = jax.grad(transformation, argnum=i)
else:
raise TequilaException(
"Can't differentiate without autograd or jax")
# We can detect one simple case where the outer derivative is const=1
if objective.transformation is None:
outer = 1.0
else:
outer = Objective(args=args, transformation=df)
if hasattr(arg, "U"):
# save redundancies
if arg in processed_expectationvalues:
inner = processed_expectationvalues[arg]
else:
inner = __grad_inner(arg=arg, variable=variable)
processed_expectationvalues[arg] = inner
else:
# this means this inner derivative is purely variable dependent
inner = __grad_inner(arg=arg, variable=variable)
if inner == 0.0:
# don't pile up zero expectationvalues
continue
if dO is None:
dO = outer * inner
else:
dO = dO + outer * inner
if dO is None:
raise TequilaException("caught None in __grad_objective")
return dO
def get_qng_combos(objective,
func=stokes_block,
initial_values=None,
samples=None,
backend=None,
device=None,
noise=None) -> typing.List[typing.Dict]:
"""
get all the objects needed to evaluate the qng for some objective; return them in a list of dictionaries.
Parameters
----------
objective: Objective:
the Objective whose qng is sought.
func: callable: (Default = stokes_block):
the function used to obtain the (blocks of) the qgt. Default uses stokes_block, defined above.
initial_values: dict, optional:
a dictionary indicating the intial parameters with which to compile all objectives appearing in the qng.
samples: int, optional:
the number of samples with which to compile all objectives appearing in the qng. Default: none.
backend: str, optional:
the backend with which to compile all objectives appearing in the qng. default: pick for you.
device: optional:
the device with which to compile all objectives appearing in the qng. Default: no device use or emulation.
noise: str or NoiseModel, optional:
the noise model with which to compile all objectives appearing in the qng. Default: no noise.
Returns
-------
list of dicts:
a list of dictionaries, each entry corresponding to the qng for 1 argument of objective, in the order
of said objectives.
"""
combos = []
vars = objective.extract_variables()
compiled = compile_multitarget(gate=objective)
compiled = compile_trotterized_gate(gate=compiled)
compiled = compile_h_power(gate=compiled)
compiled = compile_power_gate(gate=compiled)
compiled = compile_controlled_phase(gate=compiled)
compiled = compile_controlled_rotation(gate=compiled)
for i, arg in enumerate(compiled.args):
if not isinstance(arg, ExpectationValueImpl):
### this is a variable, no QNG involved
mat = QngMatrix([[[1]]])
vec = CallableVector([__grad_inner(arg, arg)])
mapping = {0: {v: __grad_inner(arg, v) for v in vars}}
else:
### if the arg is an expectationvalue, we need to build some qngs and mappings!
blocks = func(arg,
initial_values=initial_values,
samples=samples,
device=device,
backend=backend,
noise=noise)
mat = QngMatrix(blocks)
vec = subvector_procedure(arg,
initial_values=initial_values,
samples=samples,
device=device,
backend=backend,
noise=noise)
mapping = {}
self_pars = get_self_pars(arg.U)
for j, p in enumerate(self_pars):
indict = {}
for v in p.extract_variables():
gi = __grad_inner(p, v)
if isinstance(gi, Objective):
g = compile_objective(gi,
variables=initial_values,
samples=samples,
device=device,
backend=backend,
noise=noise)
else:
g = gi
indict[v] = g
mapping[j] = indict
posarg = jax.grad(compiled.transformation, i)
p = Objective(compiled.args, transformation=posarg)
pos = compile_objective(p,
variables=initial_values,
samples=samples,
device=device,
backend=backend,
noise=noise)
combos.append(qng_dict(arg, mat, vec, mapping, pos))
return combos
def get_qng_combos(objective,
initial_values=None,
samples=None,
backend=None,
backend_options=None,
noise=None):
combos = []
vars = objective.extract_variables()
compiled = compile_multitarget(gate=objective)
compiled = compile_trotterized_gate(gate=compiled)
compiled = compile_h_power(gate=compiled)
compiled = compile_power_gate(gate=compiled)
compiled = compile_controlled_phase(gate=compiled)
compiled = compile_controlled_rotation(gate=compiled)
for i, arg in enumerate(compiled.args):
if not isinstance(arg, ExpectationValueImpl):
### this is a variable, no QNG involved
mat = QngMatrix([[[1]]])
vec = CallableVector([__grad_inner(arg, arg)])
mapping = {0: {v: __grad_inner(arg, v) for v in vars}}
else:
### if the arg is an expectationvalue, we need to build some qngs and mappings!
blocks = qng_metric_tensor_blocks(arg,
initial_values=initial_values,
samples=samples,
backend=backend,
noise=noise,
backend_options=backend_options)
mat = QngMatrix(blocks)
vec = subvector_procedure(arg,
initial_values=initial_values,
samples=samples,
backend=backend,
noise=noise,
backend_options=backend_options)
mapping = {}
self_pars = get_self_pars(arg.U)
for j, p in enumerate(self_pars):
indict = {}
for v in p.extract_variables():
gi = __grad_inner(p, v)
if isinstance(gi, Objective):
g = compile_objective(gi,
variables=initial_values,
samples=samples,
backend=backend,
noise=noise,
backend_options=backend_options)
else:
g = gi
indict[v] = g
mapping[j] = indict
posarg = jax.grad(compiled.transformation, argnums=i)
p = Objective(compiled.args, transformation=posarg)
pos = compile_objective(p,
variables=initial_values,
samples=samples,
backend=backend,
noise=noise,
backend_options=backend_options)
combos.append(qng_dict(arg, mat, vec, mapping, pos))
return combos