evaluator: modernize iterative deepening - #203
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hansbinderup
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Dec 28, 2025
hansbinderup
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The previous implementation used a more primitive way of handling iterative deepening. This commit introduces the more standard way of doing it these days. Instead of using a fixed window size we widen it based on fail high and fail low + we reduce the search depth. Also the window is scaled exponentially till a given constraint. NOTE: currently only implemented for single threaded search. Bench 752159 Signed-off-by: Hans Binderup <habi@bang-olufsen.dk>
Newer version of clang format wants to format this in different ways. Bench 752159 Signed-off-by: Hans Binderup <habi@bang-olufsen.dk>
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Pull request overview
This PR modernizes the iterative deepening implementation in the evaluator by refactoring the aspiration window logic and splitting single-threaded and multi-threaded search paths. The changes improve code organization and introduce tunable parameters for aspiration window behavior.
Key Changes:
- Introduced
AspirationWindowstruct to encapsulate aspiration window logic with dynamic widening behavior - Split iterative deepening into separate methods for single-threaded (
iterativeDeepeningSingle) and multi-threaded (iterativeDeepeningMulti) execution - Added two new SPSA tunable parameters:
aspirationMinDepthandaspirationMaxWindow
Reviewed changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.
| File | Description |
|---|---|
| src/spsa/parameters.h | Adds tunable parameters for aspiration window minimum depth and maximum window size |
| src/evaluation/evaluator.h | Refactors iterative deepening with new AspirationWindow struct and separate single/multi-threaded implementations |
| src/core/board_defs.h | Adds clang-format directives around array initialization |
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