Programming search engines
[Functionality by programming task]
Enumerations | |
| enum | Gecode::SpaceStatus { Gecode::SS_FAILED, Gecode::SS_SOLVED, Gecode::SS_BRANCH } |
Space status More... | |
Functions | |
| SpaceStatus | Gecode::Space::status (StatusStatistics &stat=unused_status) |
| Query space status. | |
| const Choice * | Gecode::Space::choice (void) |
| Create new choice for current brancher. | |
| const Choice * | Gecode::Space::choice (Archive &e) const |
| Create new choice from e. | |
| Space * | Gecode::Space::clone (bool share=true, CloneStatistics &stat=unused_clone) const |
| Clone space. | |
| void | Gecode::Space::commit (const Choice &c, unsigned int a, CommitStatistics &stat=unused_commit) |
| Commit choice c for alternative a. | |
Enumeration Type Documentation
| enum Gecode::SpaceStatus |
Function Documentation
| SpaceStatus Gecode::Space::status | ( | StatusStatistics & | stat = unused_status |
) | [inherited] |
Query space status.
Propagates the space until fixpoint or failure; updates the statistics information stat; and:
- if the space is failed, SpaceStatus::SS_FAILED is returned.
- if the space is not failed but the space has no brancher left, SpaceStatus::SS_SOLVED is returned.
- otherwise, SpaceStatus::SS_BRANCH is returned.
| const Choice * Gecode::Space::choice | ( | void | ) | [inherited] |
Create new choice for current brancher.
This member function can only be called after the member function Space::status on the same space has been called and in between no non-const member function has been called on this space.
Moreover, the member function can only be called at most once (otherwise, it might generate conflicting choices).
Note that the above invariant only pertains to calls of member functions of the same space. If the invariant is violated, the system is likely to crash (hopefully it does). In particular, if applied to a space with no current brancher, the system will crash.
After a new choice has been created, no older choices can be used on the space.
If the status() member function has returned that the space has no more branchers (that is, the result was either SS_FAILED or SS_SOLVED), a call to choice() will return NULL and purge all remaining branchers inside the space. This is interesting for the case SS_SOLVED, where the call to choice can serve as garbage collection.
Throws an exception of type SpaceNotStable when applied to a not yet stable space.
| const Choice * Gecode::Space::choice | ( | Archive & | e | ) | const [inherited] |
| Space * Gecode::Space::clone | ( | bool | share = true, |
|
| CloneStatistics & | stat = unused_clone | |||
| ) | const [inline, inherited] |
Clone space.
Assumes that the space is stable and not failed. If the space is failed, an exception of type SpaceFailed is thrown. If the space is not stable, an exception of SpaceNotStable is thrown.
Otherwise, a clone of the space is returned and the statistics information stat is updated. If share is true, sharable datastructures are shared among the clone and the original space. If share is false, independent copies of the shared datastructures must be created. This means that a clone with no sharing can be used in a different thread without any interaction with the original space.
| void Gecode::Space::commit | ( | const Choice & | c, | |
| unsigned int | a, | |||
| CommitStatistics & | stat = unused_commit | |||
| ) | [inline, inherited] |
Commit choice c for alternative a.
The current brancher in the space performs a commit from the information provided by the choice c and the alternative a. The statistics information stat is updated.
Note that no propagation is perfomed (to support path recomputation), in order to perform propagation the member function status must be used.
Committing with choices must be carried out in the same order as the choices have been obtained by the member function Space::choice().
It is perfectly okay to add constraints interleaved with choices (provided they are in the right order). However, if propagation is performed by calling the member function status and then new choices are computed, these choices are different.
Only choices can be used that are up-to-date in the following sense: if a new choice is created (via the choice member function), no older choices can be used.
Committing throws the following exceptions:
- SpaceNoBrancher, if the space has no current brancher (it is already solved).
- SpaceIllegalAlternative, if a is not smaller than the number of alternatives supported by the choice c.