{
  "instance_id": "assignment_medium_s42",
  "problem_type": "assignment",
  "size": "medium",
  "seed": 42,
  "label": "Assignment (medium)",
  "features": {
    "general": {
      "n_variables": 100,
      "n_constraints": 20,
      "pct_binary": 1.0,
      "pct_integer": 1.0,
      "sparsity": 0.1,
      "coefficient_range": 100.0,
      "constraint_tightness": 0.5
    },
    "graph": {
      "graph_density": 1.0,
      "clustering_coefficient": 0.0,
      "avg_degree": 10,
      "connected_components": 1,
      "treewidth_approx": 10
    },
    "problem": {
      "n_machines": 10,
      "n_jobs": 10,
      "capacity_utilization": 0.0,
      "customer_clustering": 0.0,
      "demand_variance": 0.0,
      "time_window_tightness": 0.0
    }
  },
  "feature_vector": [
    0.1,
    0.04,
    1.0,
    1.0,
    0.1,
    1.0,
    0.5,
    1.0,
    0.0,
    0.5,
    0.1,
    0.2,
    0.2,
    0.1,
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  "prediction": {
    "recommended_solver": "cp_sat",
    "recommended_config": {
      "time_limit_sec": 10,
      "num_search_workers": 4,
      "presolve": true,
      "search_branching": "automatic",
      "heuristic_frequency": 0.5
    },
    "confidence": 0.684,
    "predicted_runtime_sec": 0.42,
    "predicted_gap_pct": 3.125,
    "feasible_probability": 0.92,
    "rationale": "Assignment (medium): 100 variables, 20 constraints | Structure: binary=100%, integer=100%, tightness=0.50 | Top pick: OR-Tools CP-SAT (score=1.361, pred gap=3.1%, feasible=92%) | Runner-up: MiniZinc (\u0394=0.074)",
    "rankings": [
      {
        "solver_id": "cp_sat",
        "score": 1.3606,
        "predicted_runtime_sec": 0.42,
        "predicted_gap_pct": 3.125,
        "feasible_probability": 0.92,
        "config": {
          "time_limit_sec": 10,
          "num_search_workers": 4,
          "presolve": true,
          "search_branching": "automatic",
          "heuristic_frequency": 0.5
        }
      },
      {
        "solver_id": "minizinc",
        "score": 1.2862,
        "predicted_runtime_sec": 0.6,
        "predicted_gap_pct": 3.5,
        "feasible_probability": 0.88,
        "config": {
          "time_limit_sec": 10,
          "solver": "chuffed",
          "neighborhood_size": 12
        }
      },
      {
        "solver_id": "alns",
        "score": 1.0608,
        "predicted_runtime_sec": 0.456,
        "predicted_gap_pct": 4.375,
        "feasible_probability": 0.89,
        "config": {
          "time_limit_sec": 10,
          "neighborhood_size": 24,
          "destroy_pct": 0.3,
          "initial_solution": "greedy"
        }
      },
      {
        "solver_id": "gurobi",
        "score": 1.0182,
        "predicted_runtime_sec": 0.36,
        "predicted_gap_pct": 1.5,
        "feasible_probability": 0.94,
        "config": {
          "time_limit_sec": 10,
          "Presolve": 2,
          "MIPFocus": 1,
          "Heuristics": 0.25,
          "Threads": 4
        }
      },
      {
        "solver_id": "scip",
        "score": 0.917,
        "predicted_runtime_sec": 0.576,
        "predicted_gap_pct": 2.5,
        "feasible_probability": 0.91,
        "config": {
          "time_limit_sec": 10,
          "presolving": true,
          "separating": true,
          "heuristics": true,
          "threads": 4
        }
      },
      {
        "solver_id": "highs",
        "score": 0.8914,
        "predicted_runtime_sec": 0.504,
        "predicted_gap_pct": 2.25,
        "feasible_probability": 0.9,
        "config": {
          "time_limit_sec": 10,
          "presolve": "on",
          "threads": 4,
          "mip_rel_gap": 0.01,
          "cut_strategy": "aggressive"
        }
      },
      {
        "solver_id": "cbc",
        "score": 0.8392,
        "predicted_runtime_sec": 0.66,
        "predicted_gap_pct": 4.0,
        "feasible_probability": 0.86,
        "config": {
          "time_limit_sec": 10,
          "presolve": "on",
          "cuts": "on",
          "heuristics": "on",
          "threads": 2
        }
      },
      {
        "solver_id": "glpk",
        "score": 0.6766,
        "predicted_runtime_sec": 0.744,
        "predicted_gap_pct": 5.625,
        "feasible_probability": 0.78,
        "config": {
          "time_limit_sec": 10,
          "presolve": true,
          "mip_gap": 0.02
        }
      }
    ]
  }
}