Package ai.timefold.solver.core.config.solver

Enum Class EnvironmentMode

java.lang.Object
java.lang.Enum<EnvironmentMode>
ai.timefold.solver.core.config.solver.EnvironmentMode
All Implemented Interfaces:
Serializable, Comparable<EnvironmentMode>, Constable
public enum EnvironmentMode extends Enum<EnvironmentMode>
The environment mode also allows you to detect common bugs in your implementation.

Also, a Solver has a single Random instance. Some optimization algorithms use the Random instance a lot more than others. For example simulated annealing depends highly on random numbers, while tabu search only depends on it to deal with score ties. This environment mode influences the seed of that Random instance.

  • Enum Constant Details

    • TRACKED_FULL_ASSERT

      public static final EnvironmentMode TRACKED_FULL_ASSERT
      This mode turns on FULL_ASSERT and enables variable tracking to fail-fast on a bug in a Move implementation, a constraint, the engine itself or something else at the highest performance cost.

      Because it tracks genuine and shadow variables, it is able to report precisely what variables caused the corruption and report any missed VariableListener events.

      This mode is reproducible (see PHASE_ASSERT mode).

      This mode is intrusive because it calls the InnerScoreDirector.calculateScore() more frequently than a non assert mode.

      This mode is by far the slowest of all the modes.

    • FULL_ASSERT

      public static final EnvironmentMode FULL_ASSERT
      This mode turns on all assertions to fail-fast on a bug in a Move implementation, a constraint, the engine itself or something else at a horrible performance cost.

      This mode is reproducible (see PHASE_ASSERT mode).

      This mode is intrusive because it calls the InnerScoreDirector.calculateScore() more frequently than a non assert mode.

      This mode is horribly slow.

    • NON_INTRUSIVE_FULL_ASSERT

      public static final EnvironmentMode NON_INTRUSIVE_FULL_ASSERT
      This mode turns on several assertions (but not all of them) to fail-fast on a bug in a Move implementation, a constraint, the engine itself or something else at an overwhelming performance cost.

      This mode is reproducible (see PHASE_ASSERT mode).

      This mode is non-intrusive, unlike FULL_ASSERT and STEP_ASSERT.

      This mode is horribly slow.

    • FAST_ASSERT

      @Deprecated(forRemoval=true, since="1.20.0") public static final EnvironmentMode FAST_ASSERT
      Deprecated, for removal: This API element is subject to removal in a future version.
      Prefer STEP_ASSERT.

    • STEP_ASSERT

      public static final EnvironmentMode STEP_ASSERT
      This mode turns on several assertions to fail-fast on a bug in a Move implementation, a constraint rule, the engine itself or something else at a reasonable performance cost (in development at least).

      This mode is reproducible (see PHASE_ASSERT mode).

      This mode is intrusive because it calls the InnerScoreDirector.calculateScore() more frequently than a non-assert mode.

      This mode is slow.

    • PHASE_ASSERT

      public static final EnvironmentMode PHASE_ASSERT
      This is the default mode as it is recommended during development, and runs minimal correctness checks that serve to quickly identify score corruption bugs.

      In this mode, two runs on the same computer will execute the same code in the same order. They will also yield the same result, except if they use a time based termination and they have a sufficiently large difference in allocated CPU time. This allows you to benchmark new optimizations (such as a new Move implementation) fairly and reproduce bugs in your code reliably.

      Warning: some code can disrupt reproducibility regardless of this mode. This typically happens when user code serves data such as planning entities from collections without defined iteration order, such as HashSet or HashMap.

      In practice, this mode uses the default random seed, and it also disables certain concurrency optimizations, such as work stealing.

    • REPRODUCIBLE

      @Deprecated(forRemoval=true, since="1.20.0") public static final EnvironmentMode REPRODUCIBLE
      Deprecated, for removal: This API element is subject to removal in a future version.
      Prefer NO_ASSERT.

    • NO_ASSERT

      public static final EnvironmentMode NO_ASSERT
      As defined by PHASE_ASSERT, but disables every single bug detection mechanism. This mode will run negligibly faster than PHASE_ASSERT, but will allow some bugs in user code (such as score corruptions) to go unnoticed. Use this mode when you are confident that your code is bug-free, or when you want to ignore a known bug temporarily.

    • NON_REPRODUCIBLE

      public static final EnvironmentMode NON_REPRODUCIBLE
      The non-reproducible mode is equally fast or slightly faster than NO_ASSERT.

      The random seed is different on every run, which makes it more robust against an unlucky random seed. An unlucky random seed gives a bad result on a certain data set with a certain solver configuration. Note that in most use cases, the impact of the random seed is relatively low on the result. An occasional bad result is far more likely to be caused by another issue (such as a score trap).

      In multithreaded scenarios, this mode allows the use of work stealing and other non-deterministic speed tricks.

  • Method Details

    • values

      public static EnvironmentMode[] values()
      Returns an array containing the constants of this enum class, in the order they are declared.
      Returns:
      an array containing the constants of this enum class, in the order they are declared

    • valueOf

      public static EnvironmentMode valueOf(String name)
      Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)
      Parameters:
      name - the name of the enum constant to be returned.
      Returns:
      the enum constant with the specified name
      Throws:
      IllegalArgumentException - if this enum class has no constant with the specified name
      NullPointerException - if the argument is null

    • isStepAssertOrMore

      public boolean isStepAssertOrMore()

    • isAsserted

      public boolean isAsserted()

    • isFullyAsserted

      public boolean isFullyAsserted()

    • isNonIntrusiveFullAsserted

      @Deprecated(forRemoval=true, since="1.20.0") public boolean isNonIntrusiveFullAsserted()
      Deprecated, for removal: This API element is subject to removal in a future version.
      Use isFullyAsserted() instead.

    • isIntrusivelyAsserted

      public boolean isIntrusivelyAsserted()

    • isIntrusiveFastAsserted

      @Deprecated(forRemoval=true, since="1.20.0") public boolean isIntrusiveFastAsserted()
      Deprecated, for removal: This API element is subject to removal in a future version.
      Use isIntrusivelyAsserted() instead.

    • isReproducible

      public boolean isReproducible()

    • isTracking

      public boolean isTracking()