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Catalog and Metadata

MOProblems.jl stores static information about each benchmark in META. The catalog API supports name-based and property-based discovery without requiring every problem to be instantiated first.

List and filter problems

using MOProblems

names = get_problem_names()
dtlz_names = filter_problems(name_pattern = r"^DTLZ")
bounded = filter_problems(has_bounds = true)
bounded_with_jacobians = filter_problems(
    has_bounds = true,
    has_jacobian = true,
)

All supplied criteria are combined. Other filters cover default dimensions, constraint counts, registered Hessians, constraint derivatives, and strict-convexity metadata. See filter_problems for the complete keyword list.

Dimension specifications

Every catalog entry owns one explicit dimension specification:

  • FixedDimension: nvar and nobj are fixed;
  • VariableNvar: n selects nvar, while nobj remains fixed;
  • VariableNobj: m selects nobj, while nvar remains fixed;
  • IndependentDimension: nvar and nobj are selected independently;
  • ParametricDimension: formulation parameters derive both dimensions;
  • CoupledDimension: selecting nvar determines nobj through a structural relation.

Dimension categories can be filtered directly:

fixed = filter_problems(dimension_type = FixedDimension)
parametric = filter_problems(dimension_type = ParametricDimension)

Constructor parameters follow the corresponding formulation. For example:

zdt = ZDT1(50)                # nvar = 50, nobj = 2
dtlz = DTLZ2(k = 8, m = 4)   # nvar = 11, nobj = 4
toi = Toi10(n = 6)            # nvar = 6, nobj = 5
mgh16 = MGH16(m = 7)          # nvar = 4, nobj = 7
mgh33 = MGH33(n = 10, m = 4) # nvar = 10, nobj = 4

Once constructed, every problem instance has fixed nvar and nobj fields.

Defaults and numeric filters

Numeric catalog filters compare against the default instance represented by the metadata:

meta = META["DTLZ2"]
nvar = default_nvar(meta)
nobj = default_nobj(meta)

small_defaults = filter_problems(max_vars = 5, max_objs = 3)

Changing constructor parameters does not change the static catalog default.

Structural metadata

ProblemMeta records bounds, constraints, derivative registration, dimension information, and per-objective strict-convexity information when available. For example:

meta = META["AP1"]

meta.has_bounds
meta.has_jacobian
meta.strict_convexity

The recognized strict-convexity values are :strictly_convex and :not_strictly_convex. A value of nothing means that reliable information is not available for the complete objective vector. Problems with unavailable information are excluded whenever a strict-convexity filter is requested, including when the requested predicate is false.