def solve(self):
T = self.g.size
with self.profiler("Gurobi model optimization", extra_data={"T": str(T), "budget": str(self.budget)}):
with Timer("ILPSolve") as solve_ilp:
self.m.optimize()
self.solve_time = solve_ilp.elapsed
infeasible = self.m.status == GRB.INFEASIBLE
try:
_ = self.R[0, 0].X
_ = self.S[0, 0].X
_ = self.U[0, 0].X
_ = self.batch_size.X
except AttributeError as e:
infeasible = True
if infeasible:
raise ValueError("Infeasible model, check constraints carefully. Insufficient memory?")
Rout = np.zeros((T, T), dtype=SOLVER_DTYPE)
Sout = np.zeros((T, T), dtype=SOLVER_DTYPE)
Uout = np.zeros((T, T), dtype=SOLVER_DTYPE)
Free_Eout = np.zeros((T, len(self.g.edge_list)), dtype=SOLVER_DTYPE)
batch_size = self.batch_size.X
try:
for t in range(T):
for i in range(T):
Rout[t][i] = int(self.R[t, i].X)
Sout[t][i] = int(self.S[t, i].X)
Uout[t][i] = self.U[t, i].X * self.ram_gcd
for e in range(len(self.g.edge_list)):
Free_Eout[t][e] = int(self.Free_E[t, e].X)
except AttributeError as e:
logging.exception(e)
return None, None, None, None
Rout = solve_r_opt(self.g, Sout) # prune R using optimal recomputation solver
ilp_aux_data = ILPAuxData(
U=Uout,
Free_E=Free_Eout,
ilp_approx=False,
ilp_time_limit=0,
ilp_eps_noise=0,
ilp_num_constraints=self.m.numConstrs,
ilp_num_variables=self.m.numVars,
)
schedule, aux_data = schedule_from_rs(self.g, Rout, Sout)
return (
ScheduledResult(
solve_strategy=SolveStrategy.OPTIMAL_ILP_GC,
solver_budget=self.budget,
feasible=True,
schedule=schedule,
schedule_aux_data=aux_data,
solve_time_s=self.solve_time,
ilp_aux_data=ilp_aux_data,
),
batch_size,
)
def solve_chen_greedy(g: DFGraph,
segment_mem_B: int,
use_actuation_points: bool = True):
with Timer("solve_chen_greedy") as timer_solve:
C = g.articulation_points if use_actuation_points else g.v
temp = 0
x = 0
checkpoints = set()
for v in g.topological_order_fwd:
temp += g.cost_ram[v]
if v in C and temp > segment_mem_B:
x += g.cost_ram[v]
temp = 0
checkpoints.add(v)
S = gen_s_matrix_fixed_checkpoints(g, checkpoints)
R = solve_r_opt(g, S)
schedule, aux_data = schedule_from_rs(g, R, S)
return ScheduledResult(
solve_strategy=SolveStrategy.CHEN_GREEDY
if use_actuation_points else SolveStrategy.CHEN_GREEDY_NOAP,
solver_budget=segment_mem_B,
feasible=True,
schedule=schedule,
schedule_aux_data=aux_data,
solve_time_s=timer_solve.elapsed,
)
def solve_checkpoint_all(g: DFGraph):
with Timer("solve_checkpoint_all") as timer_solve:
s = gen_s_matrix_fixed_checkpoints(g, g.vfwd)
r = solve_r_opt(g, s)
schedule, aux_data = schedule_from_rs(g, r, s)
return ScheduledResult(
solve_strategy=SolveStrategy.CHECKPOINT_ALL,
solver_budget=0,
feasible=True,
schedule=schedule,
schedule_aux_data=aux_data,
solve_time_s=timer_solve.elapsed,
)
def solve_checkpoint_last_node(g: DFGraph):
"""Checkpoint only one node between stages"""
with Timer("solve_checkpoint_last_node") as timer_solve:
s = np.zeros((g.size, g.size), dtype=SOLVER_DTYPE)
np.fill_diagonal(s[1:], 1)
r = solve_r_opt(g, s)
schedule, aux_data = schedule_from_rs(g, r, s)
return ScheduledResult(
solve_strategy=SolveStrategy.CHECKPOINT_LAST_NODE,
solver_budget=0,
feasible=True,
schedule=schedule,
schedule_aux_data=aux_data,
solve_time_s=timer_solve.elapsed,
)
def solve_chen_sqrtn(g: DFGraph,
use_actuation_points: bool = True) -> ScheduledResult:
with Timer("solve_chen_sqrtn") as timer_solve:
C = g.articulation_points if use_actuation_points else g.v
k = int(math.sqrt(len(C)))
checkpoints = [v for idx, v in enumerate(C) if (idx + 1) % k == 0]
S = gen_s_matrix_fixed_checkpoints(g, set(checkpoints))
R = solve_r_opt(g, S)
schedule, aux_data = schedule_from_rs(g, R, S)
return ScheduledResult(
solve_strategy=SolveStrategy.CHEN_SQRTN
if use_actuation_points else SolveStrategy.CHEN_SQRTN_NOAP,
solver_budget=0,
feasible=True,
schedule=schedule,
schedule_aux_data=aux_data,
solve_time_s=timer_solve.elapsed,
)
def solve_checkmate_cvxpy(
g, budget, rounding_thresholds=(0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9), solver_override=None, verbose=True
):
lpsolver = ILPSolverCVXPY(g, int(0.9 * budget)) # rounding threshold
try:
r, s, u, free_e = lpsolver.solve(solver_override=solver_override, verbose=verbose)
lp_feasible = True
except ValueError as e:
logging.exception(e)
r, s, u, free_e = (None, None, None, None)
lp_feasible = False
schedule, aux_data, min_threshold = None, None, None
if lp_feasible: # round the solution
for threshold in rounding_thresholds:
s_ = (s >= threshold).astype(np.int)
r_ = solve_r_opt(g, s_)
schedule_, aux_data_ = schedule_from_rs(g, r_, s_)
if aux_data_.activation_ram <= budget and (aux_data is None or aux_data_.cpu <= aux_data.cpu):
aux_data = aux_data_
schedule = schedule_
min_threshold = threshold
solve_strategy = (
SolveStrategy.APPROX_DET_ROUND_LP_05_THRESH
if len(rounding_thresholds) == 1
else SolveStrategy.APPROX_DET_ROUND_LP_SWEEP
)
return ScheduledResult(
solve_strategy=solve_strategy,
solver_budget=budget,
feasible=lp_feasible and aux_data is not None,
schedule=schedule,
schedule_aux_data=aux_data,
solve_time_s=lpsolver.solve_time,
ilp_aux_data=ILPAuxData(
U=u,
Free_E=free_e,
ilp_approx=False,
ilp_time_limit=None,
ilp_eps_noise=0.0,
ilp_num_constraints=lpsolver.num_vars,
ilp_num_variables=lpsolver.num_constraints,
approx_deterministic_round_threshold=min_threshold,
),
)
def solve_approx_lp_deterministic_sweep(
g: DFGraph,
budget: int,
seed_s: Optional[np.ndarray] = None,
approx=True,
time_limit: Optional[int] = None,
write_log_file: Optional[PathLike] = None,
print_to_console=True,
write_model_file: Optional[PathLike] = None,
eps_noise=0.01,
solver_cores=os.cpu_count(),
thresholds=(0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9),
imposed_schedule: ImposedSchedule = ImposedSchedule.FULL_SCHEDULE,
allow_return_infeasible_schedule=False,
):
param_dict = {
"LogToConsole": 1 if print_to_console else 0,
"LogFile": str(write_log_file) if write_log_file is not None else "",
"Threads": solver_cores,
"TimeLimit": math.inf if time_limit is None else time_limit,
"OptimalityTol": 1e-2 if approx else 1e-4,
"IntFeasTol": 1e-3 if approx else 1e-5,
"Presolve": 2,
"StartNodeLimit": 10000000,
}
lpsolver = ILPSolverGurobi(
g,
int(0.9 * budget), # hack to get values under the budget
gurobi_params=param_dict,
seed_s=seed_s,
integral=False,
solve_r=False,
eps_noise=eps_noise,
imposed_schedule=imposed_schedule,
write_model_file=write_model_file,
)
lpsolver.build_model()
try:
r, s, u, free_e = lpsolver.solve()
lp_feasible = True
except ValueError as e:
logging.exception(e)
r, s, u, free_e = (None, None, None, None)
lp_feasible = False
schedule, aux_data, min_threshold = None, None, None
if lp_feasible: # round the solution
for threshold in thresholds:
s_ = (s >= threshold).astype(np.int)
r_ = solve_r_opt(g, s_)
schedule_, aux_data_ = schedule_from_rs(g, r_, s_)
if (allow_return_infeasible_schedule and aux_data is None) or (
aux_data_.activation_ram <= budget and
(aux_data is None or aux_data_.cpu <= aux_data.cpu)):
aux_data = aux_data_
schedule = schedule_
min_threshold = threshold
return ScheduledResult(
solve_strategy=SolveStrategy.APPROX_DET_ROUND_LP_SWEEP,
solver_budget=budget,
feasible=lp_feasible and aux_data is not None,
schedule=schedule,
schedule_aux_data=aux_data,
solve_time_s=lpsolver.solve_time,
ilp_aux_data=ILPAuxData(
U=u,
Free_E=free_e,
ilp_approx=approx,
ilp_time_limit=time_limit,
ilp_eps_noise=eps_noise,
ilp_num_constraints=lpsolver.m.numConstrs,
ilp_num_variables=lpsolver.m.numVars,
approx_deterministic_round_threshold=min_threshold,
),
)
def solve_approx_lp_randomized(
g: DFGraph,
budget: int,
seed_s: Optional[np.ndarray] = None,
approx=True,
time_limit: Optional[int] = None,
write_log_file: Optional[PathLike] = None,
print_to_console=True,
write_model_file: Optional[PathLike] = None,
eps_noise=0.01,
solver_cores=os.cpu_count(),
num_rounds=100,
return_rounds=False,
):
"""Randomized rounding of LP relaxation
Args:
g:
budget:
seed_s:
approx:
time_limit:
write_log_file:
print_to_console:
write_model_file:
eps_noise:
solver_cores:
num_rounds:
return_rounds: If True, return tuple (ScheduledResult, rounding_statistics)
"""
param_dict = {
"LogToConsole": 1 if print_to_console else 0,
"LogFile": str(write_log_file) if write_log_file is not None else "",
"Threads": solver_cores,
"TimeLimit": math.inf if time_limit is None else time_limit,
"OptimalityTol": 1e-2 if approx else 1e-4,
"IntFeasTol": 1e-3 if approx else 1e-5,
"Presolve": 2,
"StartNodeLimit": 10000000,
}
lpsolver = ILPSolverGurobi(
g,
int(0.9 * budget), # hack to get values under the budget
gurobi_params=param_dict,
seed_s=seed_s,
solve_r=False,
integral=False,
eps_noise=eps_noise,
write_model_file=write_model_file,
)
lpsolver.build_model()
try:
r, s, u, free_e = lpsolver.solve()
lp_feasible = True
except ValueError as e:
logging.exception(e)
r, s, u, free_e = (None, None, None, None)
lp_feasible = False
best_solution = (float("inf"), None, None)
rounding_cpus = []
rounding_activation_rams = []
rounding_in_budgets = []
if lp_feasible: # round the solution
for i in range(num_rounds):
s_ = (np.random.rand(*s.shape) <= s).astype(np.int32)
r_ = solve_r_opt(g, s_)
schedule, aux_data = schedule_from_rs(g, r_, s_)
rounding_cpus.append(aux_data.cpu)
rounding_activation_rams.append(aux_data.activation_ram)
rounding_in_budgets.append(aux_data.activation_ram <= budget)
if aux_data.activation_ram <= budget and (
best_solution[2] is None
or aux_data.cpu <= best_solution[0]):
best_solution = (aux_data.cpu, schedule, aux_data)
if (i + 1) % 1 == 0:
print(
f"Rounded relaxation argmin {i+1} / num_rounds times, best cost {best_solution[0]}"
)
schedule, aux_data = best_solution[1], best_solution[2]
scheduled_result = ScheduledResult(
solve_strategy=SolveStrategy.APPROX_RANDOMIZED_ROUND,
solver_budget=budget,
feasible=lp_feasible,
schedule=schedule,
schedule_aux_data=aux_data,
solve_time_s=lpsolver.solve_time,
ilp_aux_data=ILPAuxData(
U=u,
Free_E=free_e,
ilp_approx=approx,
ilp_time_limit=time_limit,
ilp_eps_noise=eps_noise,
ilp_num_constraints=lpsolver.m.numConstrs,
ilp_num_variables=lpsolver.m.numVars,
approx_deterministic_round_threshold=None,
),
)
if return_rounds:
return (
scheduled_result,
{
"cpu": rounding_cpus,
"activation_ram": rounding_activation_rams,
"in_budget": rounding_in_budgets
},
)
return scheduled_result
def solve_ilp_gurobi(
g: DFGraph,
budget: int,
seed_s: Optional[np.ndarray] = None,
approx=True,
imposed_schedule: ImposedSchedule = ImposedSchedule.FULL_SCHEDULE,
solve_r=True,
time_limit: Optional[int] = None,
write_log_file: Optional[PathLike] = None,
print_to_console=True,
write_model_file: Optional[PathLike] = None,
eps_noise=0.01,
solver_cores=os.cpu_count(),
):
"""
Memory-accurate solver with garbage collection.
:param g: DFGraph -- graph definition extracted from model
:param budget: int -- budget constraint for solving
:param seed_s: np.ndarray -- optional parameter to set warm-start for solver, defaults to empty S
:param approx: bool -- set true to return as soon as a solution is found that is within 1% of optimal
:param imposed_schedule -- selects a set of constraints on R and S that impose a schedule or require some nodes to be computed
:param solve_r -- if set, solve for the optimal R
:param time_limit: int -- time limit for solving in seconds
:param write_log_file: if set, log gurobi to this file
:param print_to_console: if set, print gurobi logs to the console
:param write_model_file: if set, write output model file to this location
:param eps_noise: float -- if set, inject epsilon noise into objective weights, default 0.5%
:param solver_cores: int -- if set, use this number of cores for ILP solving
"""
param_dict = {
"LogToConsole": 1 if print_to_console else 0,
"LogFile": str(write_log_file) if write_log_file is not None else "",
"Threads": solver_cores,
"TimeLimit": math.inf if time_limit is None else time_limit,
"OptimalityTol": 1e-2 if approx else 1e-4,
"IntFeasTol": 1e-3 if approx else 1e-5,
"Presolve": 2,
"StartNodeLimit": 10000000,
}
ilpsolver = ILPSolver(
g,
budget,
gurobi_params=param_dict,
seed_s=seed_s,
eps_noise=eps_noise,
imposed_schedule=imposed_schedule,
solve_r=solve_r,
write_model_file=write_model_file,
)
ilpsolver.build_model()
try:
r, s, u, free_e = ilpsolver.solve()
ilp_feasible = True
except ValueError as e:
logging.exception(e)
r, s, u, free_e = (None, None, None, None)
ilp_feasible = False
ilp_aux_data = ILPAuxData(
U=u,
Free_E=free_e,
ilp_approx=approx,
ilp_time_limit=time_limit,
ilp_eps_noise=eps_noise,
ilp_num_constraints=ilpsolver.m.numConstrs,
ilp_num_variables=ilpsolver.m.numVars,
ilp_imposed_schedule=imposed_schedule,
)
schedule, aux_data = schedule_from_rs(g, r, s)
return ScheduledResult(
solve_strategy=SolveStrategy.OPTIMAL_ILP_GC,
solver_budget=budget,
feasible=ilp_feasible,
schedule=schedule,
schedule_aux_data=aux_data,
solve_time_s=ilpsolver.solve_time,
ilp_aux_data=ilp_aux_data,
)