Forward-merge release/26.02 into main#834
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rgsl888prabhu merged 1 commit intomainfrom Feb 6, 2026
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This PR implements the schedule-worker model for B&B, where one thread (the scheduler) is responsible for scheduling tasks to the other threads (the workers). With this model, the CPU resources can be shared efficiently among the different tasks within the MIP solver. It also allows the scheduling policy to be changed in runtime (e.g., in the future, the solver can dynamically set the number of workers allocated to each diving heuristics at runtime). This also implements a parallel reliability branching (Section 5.7 from [1]). This also fixes the incorrect pseudocost update in each node in the B&B tree. Closes #526. Closes #445. Closes #700. Performance over the MIPLIB2017 dataset (GH200): ``` ================================================================================ main - 046eafd (1) vs reliability-branching-cuts (2) ================================================================================ Feasible solutions = 225 vs 224 (-1) Optimal solutions = 44 vs 68 (+24) Solutions with <0.1% primal gap = 109 vs 125 (+16) Average nodes explored = 7298973 vs 4300451 (-2998522, -41.081%) Shifted geomean for MIP gap = 0.2979 vs 0.2374 (-0.0605, -20.302%) Average primal gap = 11.9935 vs 11.0833 (-0.9102, -7.589%) Average primal integral per time = 19.3326 vs 30.7054 (+11.3728, +37.038%) ================================================================================ ``` ## Reference [1] T. Achterberg, “Constraint Integer Programming,” PhD, Technischen Universität Berlin, Berlin, 2007. doi: [10.14279/depositonce-1634](https://doi.org/10.14279/depositonce-1634). Authors: - Nicolas L. Guidotti (https://github.com/nguidotti) - Chris Maes (https://github.com/chris-maes) Approvers: - Chris Maes (https://github.com/chris-maes) URL: #766
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FAILURE - Unable to forward-merge due to an error, manual merge is necessary. Do not use the IMPORTANT: When merging this PR, do not use the auto-merger (i.e. the |
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Forward-merge triggered by push to release/26.02 that creates a PR to keep main up-to-date. If this PR is unable to be immediately merged due to conflicts, it will remain open for the team to manually merge. See forward-merger docs for more info.