DrawOfferLogic
Mix-in that equips a SearchAlgorithm with draw-awareness based on insufficient material and evaluation thresholds.
Bots mixing in this trait will offer a draw when neither side can force a king capture — the win condition in Dice Chess. This happens with king + at most one bishop each, no other pieces, kings safely separated and the defending king on the opposite square colour from the enemy bishop. They will accept a draw offer in the same dead-material positions, and otherwise when the position evaluation drops below −200 centipawns (down material) — so a bot never declines a position it would itself offer.
The trait is designed to be reusable — any SearchAlgorithm can gain draw logic simply by declaring:
object MyBot extends SearchAlgorithm with DrawOfferLogic
Why separate from SearchAlgorithm
The base SearchAlgorithm defaults both draw methods to false so that simple bots remain silent. This trait packages a single, consistent draw policy that can be composed with any strategy without code duplication.
Attributes
- Source
- DrawOfferLogic.scala
- Graph
-
- Supertypes
- Known subtypes
-
object MonteCarloSearch
Members list
Value members
Concrete methods
Accepts a draw when the position is a dead draw by shouldOfferDraw's own test, or when it is so unfavourable that playing on is worse than splitting the point.
Accepts a draw when the position is a dead draw by shouldOfferDraw's own test, or when it is so unfavourable that playing on is worse than splitting the point.
The second branch uses the centipawn evaluation from Evaluator.evaluate from the active side's perspective. The threshold of −200cp (a pawn's disadvantage) is deliberately conservative — it avoids accepting draws in roughly equal positions while cutting losses in clearly lost ones. The first branch keeps offering and accepting consistent: a position the bot would offer a draw in is never one it declines.
Attributes
- Definition Classes
- Source
- DrawOfferLogic.scala
Offers a draw when the position is a theoretical dead draw: neither player can ever force a king capture — the win condition in Dice Chess.
Offers a draw when the position is a theoretical dead draw: neither player can ever force a king capture — the win condition in Dice Chess.
The check requires all of the following:
- No pawns, knights, rooks, or queens on the board.
- Each side has at most one bishop.
- The two kings are not on adjacent squares.
- For every bishop on the board, the opposing king stands on a square of the opposite colour — making a diagonal attack impossible in either direction.
These constraints capture the standard "insufficient material" cases:
K vs KK+B vs K(defending king on correct colour)K+B vs K+B(one bishop each, both kings safe)
Attributes
- Definition Classes
- Source
- DrawOfferLogic.scala
Inherited methods
Estimates the winning probability in [0.0, 1.0] for the side to move. Convenience over winProbability for offer decisions, where the deciding side is the active colour; do not override it, override winProbability.
Estimates the winning probability in [0.0, 1.0] for the side to move. Convenience over winProbability for offer decisions, where the deciding side is the active colour; do not override it, override winProbability.
Attributes
- Inherited from:
- SearchAlgorithm
- Source
- SearchAlgorithm.scala
Finds the best full-turn path, drawing any randomness (e.g. tie-breaking among equally-valued turns) from the supplied random. Lets a caller make a whole game reproducible from one seed — most importantly the bot arena, which otherwise gets a fresh unseeded Random per move and so is non-deterministic.
Finds the best full-turn path, drawing any randomness (e.g. tie-breaking among equally-valued turns) from the supplied random. Lets a caller make a whole game reproducible from one seed — most importantly the bot arena, which otherwise gets a fresh unseeded Random per move and so is non-deterministic.
The default ignores random and delegates to the no-arg findBestMove; randomised strategies override it to route their tie-breaking through the given source.
Attributes
- Inherited from:
- SearchAlgorithm
- Source
- SearchAlgorithm.scala
Determines whether the bot should accept (Take) or decline (Drop) a double from the opponent, taking the side to move as the responder. Kept for source and binary compatibility; it delegates to the three-argument overload.
Determines whether the bot should accept (Take) or decline (Drop) a double from the opponent, taking the side to move as the responder. Kept for source and binary compatibility; it delegates to the three-argument overload.
Value parameters
- currentStake
-
the proposed double stake (e.g. 2, 4...)
- state
-
current game state (dice pool is empty)
Attributes
- Returns
-
true to accept the double (Take), false to resign the current stake (Drop)
- Note
-
Perspective hazard: this overload evaluates the win probability of
state.activeColor. In a double decision state,state.activeColoris the player who offered the double, NOT the responder, so a caller that feeds the delivered position here asks whether the offerer should take. Callers must prefershouldAcceptDouble(state, currentStake, responder); strategies must override that overload, not this one. - Inherited from:
- SearchAlgorithm
- Source
- SearchAlgorithm.scala
Determines whether the bot should accept (Take) or decline (Drop) a double from the opponent, evaluated from the perspective of responder.
Determines whether the bot should accept (Take) or decline (Drop) a double from the opponent, evaluated from the perspective of responder.
This is the single policy point for the take/drop decision: strategies that want their own threshold or estimator override this overload. The two-argument form below only delegates here, so a policy written against it is bypassed whenever a caller names the responder explicitly (which every caller holding a doubleDecision state must, see the hazard note there).
Value parameters
- currentStake
-
the proposed double stake (e.g. 2, 4...)
- responder
-
the colour of the player responding to the double offer
- state
-
current game state (dice pool is empty); its active colour is the side to move, which in a double decision is the offerer, not the responder
Attributes
- Returns
-
true to accept the double (Take), false to resign the current stake (Drop)
- Inherited from:
- SearchAlgorithm
- Source
- SearchAlgorithm.scala
Determines whether the bot should offer a double before its dice roll.
Determines whether the bot should offer a double before its dice roll.
Value parameters
- currentStake
-
the current stake of the game
- state
-
current game state (dice pool is empty)
Attributes
- Returns
-
true to offer a double, false otherwise
- Inherited from:
- SearchAlgorithm
- Source
- SearchAlgorithm.scala
Estimates the winning probability in [0.0, 1.0] of color, whichever side is to move.
Estimates the winning probability in [0.0, 1.0] of color, whichever side is to move.
This is the estimator hook: a strategy with its own equity model (for example a Monte-Carlo rollout) overrides this method, so that both the offer decision (active colour) and the take/drop decision (responder colour) see the same estimate. The default maps the centipawn evaluation to a probability with a logistic sigmoid.
Attributes
- Inherited from:
- SearchAlgorithm
- Source
- SearchAlgorithm.scala
Inherited and Abstract methods
Finds and returns the best full-turn path according to this strategy.
Finds and returns the best full-turn path according to this strategy.
Value parameters
- state
-
the current dicechess.engine.domain.GameState;
state.activeColoridentifies the side to move
Attributes
- Returns
-
Some([[ScoredSequence]])when at least one legal path exists;Nonewhen the player must pass - Inherited from:
- SearchAlgorithm
- Source
- SearchAlgorithm.scala