fix(pumpkin-solver): Remove the terms with zero coefficients from linear constraints #269
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The bound computation in affine views assumes invertibility (through division by scale), however, the affine views `<VAR>.scale(0)` are not invertible. This commit fixes it by discarding all such terms during FlatZinc compilation
maartenflippo
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Aug 6, 2025
maartenflippo
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ImkoMarijnissen
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Nov 10, 2025
🤖 I have created a release *beep* *boop* --- ## [0.2.2](pumpkin-core-v0.2.1...pumpkin-core-v0.2.2) (2025-11-10) ### Features * Adding logging of brancher statistics on completion ([#257](#257)) ([9d26842](9d26842)) * Post equality as single predicate instead of splitting in two ([#305](#305)) ([8f43208](8f43208)) * Adding edge-finding for the disjunctive constraint ([#275](#275)) ([606a7d8](606a7d8)) * Lazy explanation for linear less than or equals ([#290](#290)) ([3515c7a](3515c7a)) * Write proofs with gzip encoding ([#264](#264)) ([83f76da](83f76da)) * Remove unnecessary variables introduced by bool2int ([#232](#232)) ([cf0b2fe](cf0b2fe)) * Use lazy explanations for BinaryEq ([#231](#231)) ([4a89a5e](4a89a5e)) * Support warm_start and ignore constraint_name search annotations ([#235](#235)) ([d7e8bb0](d7e8bb0)) ### Bug Fixes * Add pumpkin-crates to default-members ([#286](#286)) ([bf7ff80](bf7ff80)) * Correctly reporting unknown solution in optimisation and solution enumeration ([#247](#247)) ([8c0f27c](8c0f27c)) * Create correct reason for preprocessing permanent nogood + Removing unassigned status for PredicateId ([#250](#250)) ([98ba136](98ba136)) * Provide `SelectionContext` instead of `Assignments` to `Brancher::synchronise` ([#312](#312)) ([9548114](9548114)) * Remove debug printing ([#254](#254)) ([0ca93a2](0ca93a2)) * Remove the terms with zero coefficients from linear constraints ([#269](#269)) ([576887e](576887e)) * Take root-propagation into account in the LUS optimiser ([#253](#253)) ([d30ed06](d30ed06)) * Reduce cost of predicate notification ([#259](#259)) ([d38e990](d38e990)) ### Refactors * Avoid unnecessary traversals of profiles in time-tabling + Improving Explanations ([#282](#282)) ([f7a4fdb](f7a4fdb)) * Don't use binary equals when logging the full proof ([#252](#252)) ([4454d93](4454d93)) --- This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please). --------- Co-authored-by: Imko Marijnissen <imko.marijnissen@gmail.com>
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Consider the following FlatZinc input:
The current version of the solver crashes with division by zero, because it creates the affine views for all the terms. The bound computation in affine views assumes invertibility (through division by scale), however, affine views of the form
<VAR>.scale(0)are not invertible.This PR fixes this bug by discarding all such terms during FlatZinc compilation. I also add all three models I used for testing; all of them crash on
mainbut successfully terminate in this branch.