refactor(cost-model): use linear costing for valueContains #7476
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Change valueContains costing from multiplied_sizes to
const_above_diagonal with linear_in_x_and_y inner model.
The new model:
- Above diagonal (y > x): constant cost (early exit, returns False)
- Below diagonal (x >= y): intercept + slope1*x + slope2*y
This better reflects the actual complexity bound O(m*log(n/m+1))
which Kenneth MacKenzie showed is bounded above by a linear function.
Changes:
- models.R: Update valueContainsModel to use const_above_diagonal
- SimpleJSON.hs: Add LinearInXAndY constructor for JSON parsing
- utils.js: Add evaluators for linear_in_x_and_y and const_above_diagonal
- builtinCostModel{A,B,C}.json: Regenerated with new model type
Contributor
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Remove const_above_diagonal optimization since benchmark data shows linear behavior regardless of input size relationship. The diagonal optimization assumed quick exit when needle size > haystack size, but benchmark measurements don't reflect this behavior.
Change valueContains benchmark to use ValueTotalSize for both container and contained arguments, enabling meaningful diagonal comparison: - When contained size > container size, containment is impossible - This allows const_above_diagonal optimization in cost model Also update R model to fit const_above_diagonal with proper diagonal filtering for above/below diagonal data points.
Revert builtinCostModel{A,B,C}.json to master to avoid unnecessary
re-indentation diff. The valueContains cost model will be updated
once new benchmarks complete with ValueTotalSize for both args.
… parameters - Changed CPU cost model from a simple linear model to a more complex model with constant and intercept values. - Updated the type from "multiplied_sizes" to "const_above_diagonal" for better accuracy in cost estimation. - Adjusted arguments for intercept, slope1, and slope2 to reflect new performance metrics.
Contributor
Author
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This PR replaces #7476 |
3 tasks
kwxm
reviewed
Dec 10, 2025
| "model": { | ||
| "arguments": { | ||
| "intercept": 386227, | ||
| "slope1": 1970, |
Contributor
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The theoretical linear upper bound of k*(m+n) would have slope1 = slope2 here, but here the two slopes are very different! I think that's OK though: the theoretical bound is very conservative and this seems to fit the data very well.
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Summary
valueContainscosting frommultiplied_sizestoconst_above_diagonalwithlinear_in_x_and_yinner modelLinearInXAndYconstructor to SimpleJSON.hs for JSON parsingMotivation
The true complexity of
valueContainsisO(m*log(n/m+1))where n is the container size and m is the contained size. Kenneth MacKenzie showed that this is bounded above by a linear function(m+n)/kfor some constant k.The new model better reflects this:
intercept + slope1*x + slope2*yChanges
models.RvalueContainsModelto useconst_above_diagonalwithlinear_in_x_and_ySimpleJSON.hsLinearInXAndYconstructor for JSON parsingutils.jslinear_in_x_and_yandconst_above_diagonalbuiltinCostModel{A,B,C}.jsonNew Cost Model Structure
Test plan
Closes https://github.com/IntersectMBO/plutus-private/issues/1984