GraphBU用图原生块单元生成MILP实例，能保持源图结构，可行性高，还能提升下游训练效果。
GraphBU是一种图原生生成器，其基本单元是局部子问题及其接口。它通过将耦合节点提升为主约束或边界变量来形成块单元，并进行兼容性检查替换。该方法保证接口分离，替换在接口松弛条件下保持可行性，且图构建对行列置换不变。在MILP实例生成中，平均图统计相似度为0.934，平均可行性约96.7%，下游Predict-and-Search训练指标平均提升8.0%。
GraphBU: MILP Instance Generation with Graph-Native Block Units
Mixed-integer linear programming (MILP) instances used for solver development are hard to obtain when models come from private or application-specific pipelines. A generator must keep the structure that solvers and learned policies rely on. Existing general generators usually choose their generation unit from a formulation template, summary statistics, local graph edits, or blocks found after recombination. These units do not explicitly record how a local part of the MILP is coupled to the rest of the instance. We propose GraphBU, a graph-native generator whose basic unit is a local subproblem plus its interface. The method promotes coupling nodes into master constraints or boundary variables and uses the resulting block units for compatibility-checked replacement. The analysis focuses on the properties needed by this construction: promotion separates interfaces, replacement can preserve feasibility under an interface-slack condition, and the graph construction is invariant to row-column permutations. On MILP instances generation, this unit keeps graph statistics close to the source family, preserves feasibility on most datasets, and improves downstream Predict-and-Search training. Genrated by GraphBU, The average graph-statistical similarity was approximately 0.934, the average feasibility was approximately 96.7%, and the average increase in the main index of downstream PS was approximately 8.0%.