{
  "instance_id": "network_design_medium_s42",
  "problem_type": "network_design",
  "size": "medium",
  "seed": 42,
  "label": "Network Design (medium)",
  "features": {
    "general": {
      "n_variables": 42,
      "n_constraints": 12,
      "pct_binary": 0.35,
      "pct_integer": 0.5,
      "sparsity": 0.1591,
      "coefficient_range": 100.0,
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    "graph": {
      "graph_density": 3.5,
      "clustering_coefficient": 0.38,
      "avg_degree": 3.5,
      "connected_components": 1,
      "treewidth_approx": 3.4641
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    "problem": {
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      "n_jobs": 0,
      "capacity_utilization": 0.58,
      "customer_clustering": 0.0,
      "demand_variance": 0.0,
      "time_window_tightness": 0.0
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  "feature_vector": [
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  "prediction": {
    "recommended_solver": "minizinc",
    "recommended_config": {
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      "solver": "chuffed",
      "neighborhood_size": 12
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    "confidence": 0.524,
    "predicted_runtime_sec": 0.542,
    "predicted_gap_pct": 3.668,
    "feasible_probability": 0.88,
    "rationale": "Network Design (medium): 42 variables, 12 constraints | Structure: binary=35%, integer=50%, tightness=0.62 | Top pick: MiniZinc (score=1.638, pred gap=3.7%, feasible=88%) | Runner-up: OR-Tools CP-SAT (\u0394=0.002)",
    "rankings": [
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        "feasible_probability": 0.88,
        "config": {
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      {
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        "predicted_gap_pct": 3.275,
        "feasible_probability": 0.92,
        "config": {
          "time_limit_sec": 10,
          "num_search_workers": 4,
          "presolve": true,
          "search_branching": "automatic",
          "heuristic_frequency": 0.5
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      {
        "solver_id": "alns",
        "score": 1.2836,
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        "predicted_gap_pct": 4.585,
        "feasible_probability": 0.89,
        "config": {
          "time_limit_sec": 10,
          "neighborhood_size": 24,
          "destroy_pct": 0.3,
          "initial_solution": "greedy"
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      {
        "solver_id": "scip",
        "score": 1.0388,
        "predicted_runtime_sec": 0.52,
        "predicted_gap_pct": 2.62,
        "feasible_probability": 0.91,
        "config": {
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          "presolving": true,
          "separating": true,
          "heuristics": true,
          "threads": 4
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      {
        "solver_id": "highs",
        "score": 0.965,
        "predicted_runtime_sec": 0.455,
        "predicted_gap_pct": 2.358,
        "feasible_probability": 0.9,
        "config": {
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          "presolve": "on",
          "threads": 4,
          "mip_rel_gap": 0.01,
          "cut_strategy": "aggressive"
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      },
      {
        "solver_id": "gurobi",
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        "predicted_gap_pct": 1.572,
        "feasible_probability": 0.94,
        "config": {
          "time_limit_sec": 10,
          "Presolve": 2,
          "MIPFocus": 1,
          "Heuristics": 0.25,
          "Threads": 4
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      },
      {
        "solver_id": "cbc",
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        "predicted_gap_pct": 4.192,
        "feasible_probability": 0.86,
        "config": {
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          "presolve": "on",
          "cuts": "on",
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          "threads": 2
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}