from optproblems import zdt, dtlz
from desdeo_problem.problem.Variable import variable_builder
from desdeo_problem.problem.Objective import VectorObjective
from desdeo_problem.problem.Problem import MOProblem
from desdeo_problem.problem.Problem import ProblemError
[docs]def test_problem_builder(name: str, n_of_variables: int = None, n_of_objectives: int = None) -> MOProblem:
"""Build test problems. Currently supported: ZDT1-4, ZDT6, and DTLZ1-7.
Args:
name (str): Name of the problem in all caps. For example: "ZDT1", "DTLZ4", etc.
n_of_variables (int, optional): Number of variables. Required for DTLZ problems,
but can be skipped for ZDT problems as they only support one variable value.
n_of_objectives (int, optional): Required for DTLZ problems,
but can be skipped for ZDT problems as they only support one variable value.
Raises:
ProblemError: When one of many issues occur while building the MOProblem
instance.
Returns:
MOProblem: The test problem object
"""
problems = {
"ZDT1": zdt.ZDT1,
"ZDT2": zdt.ZDT2,
"ZDT3": zdt.ZDT3,
"ZDT4": zdt.ZDT4,
"ZDT5": zdt.ZDT5,
"ZDT6": zdt.ZDT6,
"DTLZ1": dtlz.DTLZ1,
"DTLZ2": dtlz.DTLZ2,
"DTLZ3": dtlz.DTLZ3,
"DTLZ4": dtlz.DTLZ4,
"DTLZ5": dtlz.DTLZ5,
"DTLZ6": dtlz.DTLZ6,
"DTLZ7": dtlz.DTLZ7,
}
num_var = {"ZDT1": 30, "ZDT2": 30, "ZDT3": 30, "ZDT4": 10, "ZDT6": 10}
if not (name in problems.keys()):
msg = "Specified Problem not yet supported.\n The supported problems are:" + str(problems.keys())
raise ProblemError(msg)
if "ZDT" in name:
if n_of_variables is None:
n_of_variables = num_var[name]
if n_of_objectives is None:
n_of_objectives = 2
if not (n_of_variables == num_var[name]):
msg = (
name
+ " problem has been limited to "
+ str(num_var[name])
+ " variables. Number of variables recieved = "
+ str(n_of_variables)
)
raise ProblemError(msg)
if not (n_of_objectives == 2):
msg = (
"ZDT problems can only have 2 objectives. " + "Number of objectives recieved = " + str(n_of_objectives)
)
raise ProblemError(msg)
obj_func = problems[name]()
elif "DTLZ" in name:
if (n_of_variables is None) or (n_of_objectives is None):
msg = "Please provide both number of variables and objectives" + " for the DTLZ problems"
raise ProblemError(msg)
obj_func = problems[name](n_of_objectives, n_of_variables)
else:
msg = "How did you end up here?"
raise ProblemError(msg)
lower_limits = obj_func.min_bounds
upper_limits = obj_func.max_bounds
var_names = ["x" + str(i + 1) for i in range(n_of_variables)]
obj_names = ["f" + str(i + 1) for i in range(n_of_objectives)]
variables = variable_builder(
names=var_names,
initial_values=lower_limits,
lower_bounds=lower_limits,
upper_bounds=upper_limits,
)
# Because optproblems can only handle one objective at a time
def modified_obj_func(x):
if isinstance(x, list):
if len(x) == n_of_variables:
return [obj_func(x)]
elif len(x[0]) == n_of_variables:
return list(map(obj_func, x))
else:
if x.ndim == 1:
return [obj_func(x)]
elif x.ndim == 2:
return list(map(obj_func, x))
raise TypeError("Unforseen problem, contact developer")
objective = VectorObjective(name=obj_names, evaluator=modified_obj_func)
problem = MOProblem([objective], variables, None)
return problem
