Agent Conversation: google/gemini-3.1-pro-preview

Model: google/gemini-3.1-pro-preview
Total steps: 6
Messages: 24
UserStep 0

Task: optimization-multi-objective

Multi-Objective Optimization: Custom Evolutionary Strategy Design

Research Question

Design a novel multi-objective evolutionary algorithm (MOEA) strategy that achieves better convergence, diversity, and spread on standard benchmark problems than classic approaches like NSGA-II, MOEA/D, and SPEA2.

Background

Multi-objective optimization aims to find a set of Pareto-optimal solutions that represent the best trade-offs among conflicting objectives. Evolutionary algorithms are the dominant approach, differing primarily in three components:

  • Parent selection: How to choose individuals for mating (e.g., tournament with crowding distance, reference-vector-based).
  • Variation: How to produce offspring via crossover and mutation operators.
  • Environmental selection (survival): How to prune the combined parent+offspring pool back to population size (e.g., non-dominated sorting + crowding, decomposition into subproblems, indicator-based selection).

Classic algorithms include:

  • NSGA-II (Deb et al., 2002): Non-dominated sorting + crowding distance for diversity.
  • MOEA/D (Zhang & Li, 2007): Decomposes the problem into scalar subproblems using weight vectors.
  • SPEA2 (Zitzler et al., 2001): Strength-based fitness with density estimation via k-nearest neighbors.

State-of-the-art methods include:

  • NSGA-III (Deb & Jain, 2014): Reference-point-based selection for many-objective problems.
  • RVEA (Cheng et al., 2016): Angle-penalized distance with adaptive reference vectors.
  • AGE-MOEA (Panichella, 2019): Adaptive geometry estimation for survival selection.

There is active research into strategies that combine ideas across these paradigms, adapt to problem geometry, or use novel diversity maintenance mechanisms.

Task

Implement a custom multi-objective evolutionary strategy by modifying the CustomMOEA class in deap/custom_moea.py. You should implement the select, vary, survive, and optionally on_generation methods. The algorithm must work for both 2-objective and 3-objective problems.

Interface

class CustomMOEA:
    def __init__(self, pop_size, n_obj, n_var, bounds, cx_eta=20.0, mut_eta=20.0, mut_prob=None):
        """Initialize the MOEA with problem parameters."""

    def select(self, population: list, k: int) -> list:
        """Select k parents from the population for mating.
        Returns: list of k selected individuals."""

    def vary(self, parents: list) -> list:
        """Apply crossover and mutation to produce offspring.
        Returns: list of offspring (fitness invalidated)."""

    def survive(self, population: list, offspring: list) -> list:
        """Environmental selection: choose pop_size individuals from combined pool.
        Returns: list of pop_size individuals for next generation."""

    def on_generation(self, gen: int, population: list):
        """Optional per-generation callback for adaptive strategies."""

Ind

AssistantStep 1edit
Tool Input
1{
2  "end_line": 441,
3  "start_line": 297,
4  "content": "class CustomMOEA:\n    \"\"\"SDE-NSGA-II: Non-dominated Sorting with Shift-Based Density Estimation.\"\"\"\n\n    def __init__(\n        self,\n        pop_size: int,\n        n_obj: int,\n        n_var: int,\n        bounds: Tuple[float, float],\n        cx_eta: float = 20.0,\n        mut_eta: float = 20.0,\n        mut_prob: Optional[float] = None,\n    ):\n        self.pop_size = pop_size\n        self.n_obj = n_obj\n        self.n_var = n_var\n        self.bounds = bounds\n        self.cx_eta = cx_eta\n        self.mut_eta = mut_eta\n        self.mut_prob = mut_prob if mut_prob is not None else 1.0 / n_var\n\n    def select(self, population: list, k: int) -> list:\n        \"\"\"Tournament selection using rank and SDE distances.\"\"\"\n        selected = []\n        for _ in range(k):\n            i1, i2 = random.sample(range(len(population)), 2)\n            a, b = population[i1], population[i2]\n            \n            rank_a = getattr(a, '_rank', 0)\n            rank_b = getattr(b, '_rank', 0)\n            \n            if rank_a < rank_b:\n                selected.append(deepcopy(a))\n            elif rank_b < rank_a:\n                selected.append(deepcopy(b))\n            else:\n                cd_a = getattr(a.fitness, 'crowding_dist', 0)\n                cd_b = getattr(b.fitness, 'crowding_dist', 0)\n                if cd_a > cd_b:\n                    selected.append(deepcopy(a))\n                elif cd_b > cd_a:\n                    selected.append(deepcopy(b))\n                else:\n                    selected.append(deepcopy(random.choice([a, b])))\n        return selected\n\n    def vary(self, parents: list) -> list:\n        offspring = [deepcopy(p) for p in parents]\n        lo, hi = self.bounds\n        n = len(offspring)\n\n        # Mix SBX and Differential Evolution (DE)\n        for i in range(0, n - 1, 2):\n            if random.random() < 0.5:\n                # SBX Crossover\n                tools.cxSimulatedBinaryBounded(offspring[i], offspring[i+1], eta=self.cx_eta, low=lo, up=hi)\n                try:\n                    del offspring[i].fitness.values\n                    del offspring[i+1].fitness.values\n                except AttributeError:\n                    pass\n            else:\n                # DE Crossover for both children\n                for child_idx in (i, i+1):\n                    r1, r2, r3 = random.sample(range(n), 3)\n                    j_rand = random.randint(0, self.n_var - 1)\n                    for j in range(self.n_var):\n                        if random.random() < 0.9 or j == j_rand:\n                            val = parents[r1][j] + 0.5 * (parents[r2][j] - parents[r3][j])\n                            offspring[child_idx][j] = max(lo, min(hi, val))\n                    try:\n                        del offspring[child_idx].fitness.values\n                    except AttributeError:\n                        pass\n\n        # Polynomial Mutation\n        for ind in offspring:\n            if random.random() < 1.0:\n                tools.mutPolynomialBounded(ind, eta=self.mut_eta, low=lo, up=hi, indpb=self.mut_prob)\n                try:\n                    del ind.fitness.values\n                except AttributeError:\n                    pass\n\n        return offspring\n\n    def survive(self, population: list, offspring: list) -> list:\n        combined = population + offspring\n        fronts = tools.sortNondominated(combined, self.pop_size, first_front_only=False)\n        \n        next_gen = []\n        for rank, front in enumerate(fronts):\n            for ind in front:\n                ind._rank = rank\n                \n            if len(next_gen) + len(front) <= self.pop_size:\n                self._assign_sde_crowding(front)\n                next_gen.extend(front)\n            else:\n                remaining = self.pop_size - len(next_gen)\n                truncated_front = self._sde_truncation(front, remaining)\n                self._assign_sde_crowding(truncated_front)\n                next_gen.extend(truncated_front)\n                break\n                \n        return next_gen\n\n    def _sde_truncation(self, front, k):\n        F = np.array([ind.fitness.values for ind in front])\n        n = len(front)\n        \n        z_min = F.min(axis=0)\n        z_max = F.max(axis=0)\n        scale = np.clip(z_max - z_min, 1e-12, None)\n        F_norm = (F - z_min) / scale\n        \n        sde_mat = np.zeros((n, n))\n        for i in range(n):\n            for j in range(n):\n                if i != j:\n                    diff = np.maximum(0, F_norm[j] - F_norm[i])\n                    sde_mat[i, j] = np.sqrt(np.sum(diff**2))\n                else:\n                    sde_mat[i, j] = np.inf\n                    \n        active = list(range(n))\n        while len(active) > k:\n            sorted_dists = []\n            for i in active:\n                dists = [sde_mat[i, j] for j in active if j != i]\n                dists.sort()\n                sorted_dists.append(dists)\n                \n            worst_idx = 0\n            for i in range(1, len(active)):\n                for d_i, d_worst in zip(sorted_dists[i], sorted_dists[worst_idx]):\n                    if abs(d_i - d_worst) > 1e-12:\n                        if d_i < d_worst:\n                            worst_idx = i\n                        break\n            active.pop(worst_idx)\n            \n        return [front[i] for i in active]\n\n    def _assign_sde_crowding(self, front):\n        if len(front) <= 2:\n            for ind in front:\n                ind.fitness.crowding_dist = float('inf')\n            return\n            \n        F = np.array([ind.fitness.values for ind in front])\n        n = len(front)\n        z_min = F.min(axis=0)\n        z_max = F.max(axis=0)\n        scale = np.clip(z_max - z_min, 1e-12, None)\n        F_norm = (F - z_min) / scale\n        \n        for i in range(n):\n            min_dist = float('inf')\n            for j in range(n):\n                if i != j:\n                    diff = np.maximum(0, F_norm[j] - F_norm[i])\n                    d = np.sum(diff**2)\n                    if d < min_dist:\n                        min_dist = d\n            front[i].fitness.crowding_dist = np.sqrt(min_dist)\n\n    def on_generation(self, gen: int, population: list):\n        pass\n",
5  "filename": "deap/custom_moea.py",
6  "op": "replace"
7}
Tool ResultStep 1
OK: Replaced lines 297..441 with 169 line(s) in deap/custom_moea.py. Editable range: 297–465.

[Current file: deap/custom_moea.py | editable: 297–465 | total: 614 lines]
   294| # ================================================================
   295| 
   296| 
   297  class CustomMOEA:
   298      """SDE-NSGA-II: Non-dominated Sorting with Shift-Based Density Estimation."""
   299  
   300      def __init__(
   301          self,
   302          pop_size: int,
   303          n_obj: int,
   304          n_var: int,
   305          bounds: Tuple[float, float],
   306          cx_eta: float = 20.0,
   307          mut_eta: float = 20.0,
   308          mut_prob: Optional[float] = None,
   309      ):
   310          self.pop_size = pop_size
   311          self.n_obj = n_obj
   312          self.n_var = n_var
   313          self.bounds = bounds
   314          self.cx_eta = cx_eta
   315          self.mut_eta = mut_eta
   316          self.mut_prob = mut_prob if mut_prob is not None e
AssistantStep 2test
Tool ResultStep 2
[Test #1] (2 tests remaining; call submit(n=1) to submit this result)


## Seed 42

### zdt1 (scripts/zdt1.sh)
Training progress (last generations):
TRAIN_METRICS gen=120 hv=0.869303 igd=0.004363 spread=0.367419 front_size=100
TRAIN_METRICS gen=140 hv=0.870570 igd=0.004145 spread=0.365231 front_size=100
TRAIN_METRICS gen=160 hv=0.870548 igd=0.004157 spread=0.371205 front_size=100
TRAIN_METRICS gen=180 hv=0.870436 igd=0.004348 spread=0.380956 front_size=100
TRAIN_METRICS gen=200 hv=0.870901 igd=0.004224 spread=0.362991 front_size=100
Test results (zdt1):
  hv: 0.870901
  igd: 0.004224
  spread: 0.362991

### zdt3 (scripts/zdt3.sh)
Training progress (last generations):
TRAIN_METRICS gen=120 hv=1.324785 igd=0.005862 spread=0.668579 front_size=100
TRAIN_METRICS gen=140 hv=1.324737 igd=0.006371 spread=0.732037 front_size=100
TRAIN_METRICS gen=160 hv=1.326150 igd=0.006189 spread=0.659373 front_size=100
TRAIN_METRICS gen=180 hv=1.326179 igd=0.005565 spread=0.688672 front_size=100
TRAIN_METRIC
AssistantStep 3edit
Tool Input
1{
2  "start_line": 383,
3  "end_line": 463,
4  "content": "    def survive(self, population: list, offspring: list) -> list:\n        combined = population + offspring\n        fronts = tools.sortNondominated(combined, self.pop_size, first_front_only=False)\n        \n        F_all = np.array([ind.fitness.values for ind in combined])\n        z_min = F_all.min(axis=0)\n        z_max = F_all.max(axis=0)\n        scale = np.clip(z_max - z_min, 1e-12, None)\n        \n        next_gen = []\n        for rank, front in enumerate(fronts):\n            for ind in front:\n                ind._rank = rank\n                \n            if len(next_gen) + len(front) <= self.pop_size:\n                self._assign_sde_crowding(front, z_min, scale)\n                next_gen.extend(front)\n            else:\n                remaining = self.pop_size - len(next_gen)\n                truncated_front = self._sde_truncation(front, remaining, z_min, scale)\n                self._assign_sde_crowding(truncated_front, z_min, scale)\n                next_gen.extend(truncated_front)\n                break\n                \n        return next_gen\n\n    def _sde_truncation(self, front, k, z_min, scale):\n        F = np.array([ind.fitness.values for ind in front])\n        n = len(front)\n        \n        F_norm = (F - z_min) / scale\n        \n        sde_mat = np.zeros((n, n))\n        for i in range(n):\n            for j in range(n):\n                if i != j:\n                    diff = np.maximum(0, F_norm[j] - F_norm[i])\n                    sde_mat[i, j] = np.sqrt(np.sum(diff**2))\n                else:\n                    sde_mat[i, j] = np.inf\n                    \n        active = list(range(n))\n        while len(active) > k:\n            sorted_dists = []\n            for i in active:\n                dists = [sde_mat[i, j] for j in active if j != i]\n                dists.sort()\n                sorted_dists.append(dists)\n                \n            worst_idx = 0\n            for i in range(1, len(active)):\n                for d_i, d_worst in zip(sorted_dists[i], sorted_dists[worst_idx]):\n                    if abs(d_i - d_worst) > 1e-12:\n                        if d_i < d_worst:\n                            worst_idx = i\n                        break\n            active.pop(worst_idx)\n            \n        return [front[i] for i in active]\n\n    def _assign_sde_crowding(self, front, z_min, scale):\n        if len(front) <= 2:\n            for ind in front:\n                ind.fitness.crowding_dist = float('inf')\n            return\n            \n        F = np.array([ind.fitness.values for ind in front])\n        n = len(front)\n        F_norm = (F - z_min) / scale\n        \n        for i in range(n):\n            min_dist = float('inf')\n            for j in range(n):\n                if i != j:\n                    diff = np.maximum(0, F_norm[j] - F_norm[i])\n                    d = np.sum(diff**2)\n                    if d < min_dist:\n                        min_dist = d\n            front[i].fitness.crowding_dist = np.sqrt(min_dist)",
5  "filename": "deap/custom_moea.py",
6  "op": "replace"
7}
Tool ResultStep 3
OK: Replaced lines 383..463 with 79 line(s) in deap/custom_moea.py. Editable range: 297–463.

[Current file: deap/custom_moea.py | editable: 297–463 | total: 612 lines]
   294| # ================================================================
   295| 
   296| 
   297  class CustomMOEA:
   298      """SDE-NSGA-II: Non-dominated Sorting with Shift-Based Density Estimation."""
   299  
   300      def __init__(
   301          self,
   302          pop_size: int,
   303          n_obj: int,
   304          n_var: int,
   305          bounds: Tuple[float, float],
   306          cx_eta: float = 20.0,
   307          mut_eta: float = 20.0,
   308          mut_prob: Optional[float] = None,
   309      ):
   310          self.pop_size = pop_size
   311          self.n_obj = n_obj
   312          self.n_var = n_var
   313          self.bounds = bounds
   314          self.cx_eta = cx_eta
   315          self.mut_eta = mut_eta
   316          self.mut_prob = mut_prob if mut_prob is not None el
AssistantStep 4test
AssistantStep 1edit
Tool Input
1{
2  "start_line": 346,
3  "end_line": 440,
4  "filename": "deap/custom_moea.py",
5  "content": "    def select(self, population: list, k: int) -> list:\n        fronts = tools.sortNondominated(population, len(population), first_front_only=False)\n        for front in fronts:\n            compute_crowding_distance(front)\n        return tools.selTournamentDCD(population, k)\n\n    def vary(self, parents: list) -> list:\n        offspring = []\n        lo, hi = self.bounds\n        for i in range(len(parents)):\n            child = deepcopy(parents[i])\n            if random.random() < 0.5:\n                # DE variation\n                r1, r2, r3 = random.sample(parents, 3)\n                F_weight = random.uniform(0.4, 0.8)\n                CR = random.uniform(0.7, 1.0)\n                j_rand = random.randint(0, self.n_var - 1)\n                for j in range(self.n_var):\n                    if random.random() < CR or j == j_rand:\n                        child[j] = r1[j] + F_weight * (r2[j] - r3[j])\n                        if child[j] < lo: child[j] = lo\n                        if child[j] > hi: child[j] = hi\n            else:\n                # SBX\n                mate_idx = random.randint(0, len(parents) - 1)\n                tools.cxSimulatedBinaryBounded(child, parents[mate_idx], eta=self.cx_eta, low=lo, up=hi)\n\n            if random.random() < 1.0:\n                tools.mutPolynomialBounded(child, eta=self.mut_eta, low=lo, up=hi, indpb=self.mut_prob)\n            del child.fitness.values\n            offspring.append(child)\n        return offspring\n\n    def survive(self, population: list, offspring: list) -> list:\n        combined = population + offspring\n        fronts = tools.sortNondominated(combined, self.pop_size, first_front_only=False)\n\n        next_gen = []\n        for front in fronts:\n            if len(next_gen) + len(front) <= self.pop_size:\n                next_gen.extend(front)\n            else:\n                remaining = self.pop_size - len(next_gen)\n                F_front = np.array([ind.fitness.values for ind in front])\n                \n                z_min = np.min(F_front, axis=0)\n                z_max = np.max(F_front, axis=0)\n                scale = z_max - z_min\n                scale[scale < 1e-12] = 1.0\n                F_front_norm = (F_front - z_min) / scale\n                \n                selected_indices = []\n                min_dists = np.full(len(front), np.inf)\n                \n                if len(next_gen) > 0:\n                    F_next = np.array([ind.fitness.values for ind in next_gen])\n                    F_next_norm = (F_next - z_min) / scale\n                    for i in range(len(front)):\n                        diffs = F_next_norm - F_front_norm[i]\n                        dists = np.sum(diffs**2, axis=1)\n                        if len(dists) > 0:\n                            min_dists[i] = np.min(dists)\n                else:\n                    for m in range(self.n_obj):\n                        if len(selected_indices) >= remaining:\n                            break\n                        idx = np.argmin(F_front_norm[:, m])\n                        if idx not in selected_indices:\n                            selected_indices.append(idx)\n                            diffs = F_front_norm - F_front_norm[idx]\n                            min_dists = np.minimum(min_dists, np.sum(diffs**2, axis=1))\n                \n                while len(selected_indices) < remaining:\n                    masked_dists = min_dists.copy()\n                    masked_dists[selected_indices] = -1.0 \n                    \n                    best_idx = int(np.argmax(masked_dists))\n                    selected_indices.append(best_idx)\n                    \n                    diffs = F_front_norm - F_front_norm[best_idx]\n                    min_dists = np.minimum(min_dists, np.sum(diffs**2, axis=1))\n                    \n                next_gen.extend([front[i] for i in selected_indices])\n                break\n                \n        return next_gen\n\n    def on_generation(self, gen: int, population: list):\n        pass",
6  "op": "replace"
7}
Tool ResultStep 1
OK: Replaced lines 346..440 with 89 line(s) in deap/custom_moea.py. Editable range: 297–435.

[Current file: deap/custom_moea.py | editable: 297–435 | total: 584 lines]
   294| # ================================================================
   295| 
   296| 
   297  class CustomMOEA:
   298      """Custom multi-objective evolutionary algorithm.
   299  
   300      The agent should implement a novel evolutionary strategy for multi-objective
   301      optimization. The algorithm operates on a population of individuals, each
   302      with a fitness consisting of multiple objective values (all minimized).
   303  
   304      Available DEAP utilities (already imported):
   305          - tools.sortNondominated(pop, k) -> list of fronts
   306          - tools.selTournamentDCD(pop, k) -> selected individuals
   307          - tools.cxSimulatedBinaryBounded(ind1, ind2, eta, low, up)
   308          - tools.mutPolynomialBounded(ind, eta, low, up, indpb)
   309          - tools.unifor
AssistantStep 2test
Tool ResultStep 2
[Test #1] (2 tests remaining; call submit(n=1) to submit this result)

### zdt1 (scripts/zdt1.sh)
Training progress (last generations):
TRAIN_METRICS gen=120 hv=0.861814 igd=0.008300 spread=0.276295 front_size=100
TRAIN_METRICS gen=140 hv=0.863574 igd=0.007169 spread=0.261842 front_size=100
TRAIN_METRICS gen=160 hv=0.864249 igd=0.006943 spread=0.284282 front_size=100
TRAIN_METRICS gen=180 hv=0.865457 igd=0.006280 spread=0.308060 front_size=100
TRAIN_METRICS gen=200 hv=0.866405 igd=0.005741 spread=0.279686 front_size=100
Test results (zdt1):
  hv: 0.866405
  igd: 0.005741
  spread: 0.279686

### zdt3 (scripts/zdt3.sh)
Training progress (last generations):
TRAIN_METRICS gen=120 hv=1.309892 igd=0.008135 spread=0.501338 front_size=100
TRAIN_METRICS gen=140 hv=1.313320 igd=0.007280 spread=0.515454 front_size=100
TRAIN_METRICS gen=160 hv=1.316302 igd=0.006455 spread=0.480840 front_size=100
TRAIN_METRICS gen=180 hv=1.318929 igd=0.005904 spread=0.482375 front_size=100
TRAIN_METRICS gen=200 hv=
AssistantStep 1edit
Tool Input
1{
2  "op": "replace",
3  "content": "class CustomMOEA:\n    \"\"\"SDE-DE: Shift-Based Density Estimation with Differential Evolution.\"\"\"\n\n    def __init__(\n        self,\n        pop_size: int,\n        n_obj: int,\n        n_var: int,\n        bounds: Tuple[float, float],\n        cx_eta: float = 20.0,\n        mut_eta: float = 20.0,\n        mut_prob: Optional[float] = None,\n    ):\n        self.pop_size = pop_size\n        self.n_obj = n_obj\n        self.n_var = n_var\n        self.bounds = bounds\n        self.cx_eta = cx_eta\n        self.mut_eta = mut_eta\n        self.mut_prob = mut_prob if mut_prob is not None else 1.0 / n_var\n\n    def select(self, population: list, k: int) -> list:\n        # Assign rank and SDE density\n        fronts = tools.sortNondominated(population, len(population), first_front_only=False)\n        for rank, front in enumerate(fronts):\n            if len(front) <= 2:\n                for ind in front:\n                    ind._sde_density = float('inf')\n                    ind._rank = rank\n            else:\n                front_arr = np.array([ind.fitness.values for ind in front])\n                z_min = np.min(front_arr, axis=0)\n                z_max = np.max(front_arr, axis=0)\n                scale = z_max - z_min\n                scale[scale < 1e-12] = 1.0\n                F_norm = (front_arr - z_min) / scale\n                \n                diff_front = F_norm[np.newaxis, :, :] - F_norm[:, np.newaxis, :]\n                diff_front = np.maximum(0, diff_front)\n                dists_front = np.sqrt(np.sum(diff_front ** 2, axis=2))\n                np.fill_diagonal(dists_front, np.inf)\n                \n                sde_density = np.min(dists_front, axis=1)\n                for i, ind in enumerate(front):\n                    ind._sde_density = sde_density[i]\n                    ind._rank = rank\n\n        selected = []\n        for _ in range(k):\n            i1, i2 = random.sample(range(len(population)), 2)\n            ind1, ind2 = population[i1], population[i2]\n            \n            if ind1._rank < ind2._rank:\n                selected.append(deepcopy(ind1))\n            elif ind1._rank > ind2._rank:\n                selected.append(deepcopy(ind2))\n            else:\n                if ind1._sde_density > ind2._sde_density:\n                    selected.append(deepcopy(ind1))\n                else:\n                    selected.append(deepcopy(ind2))\n        return selected\n\n    def vary(self, parents: list) -> list:\n        offspring = []\n        lo, hi = self.bounds\n\n        for i in range(len(parents)):\n            child = deepcopy(parents[i])\n            \n            if random.random() < 0.5:\n                # Differential Evolution (DE/rand/1/bin)\n                pool = random.sample(parents, 3)\n                p1, p2, p3 = pool[0], pool[1], pool[2]\n                \n                F_w = random.uniform(0.4, 0.9)\n                CR = random.uniform(0.1, 0.9)\n                jr = random.randint(0, self.n_var - 1)\n                \n                for j in range(self.n_var):\n                    if random.random() < CR or j == jr:\n                        child[j] = p1[j] + F_w * (p2[j] - p3[j])\n                        child[j] = min(max(child[j], lo), hi)\n            else:\n                # Simulated Binary Crossover\n                mate = random.choice(parents)\n                tools.cxSimulatedBinaryBounded(\n                    child, mate,\n                    eta=self.cx_eta, low=lo, up=hi,\n                )\n            \n            # Polynomial Mutation\n            if random.random() < 1.0:\n                tools.mutPolynomialBounded(\n                    child, eta=self.mut_eta, low=lo, up=hi, indpb=self.mut_prob,\n                )\n            \n            del child.fitness.values\n            offspring.append(child)\n\n        return offspring\n\n    def survive(self, population: list, offspring: list) -> list:\n        combined = population + offspring\n        fronts = tools.sortNondominated(combined, self.pop_size, first_front_only=False)\n        \n        # Determine global normalization bounds for SDE\n        combined_arr = np.array([ind.fitness.values for ind in combined])\n        z_min = np.min(combined_arr, axis=0)\n        z_max = np.max(combined_arr, axis=0)\n        scale = z_max - z_min\n        scale[scale < 1e-12] = 1.0\n\n        next_gen = []\n        for front in fronts:\n            if len(next_gen) + len(front) <= self.pop_size:\n                next_gen.extend(front)\n            else:\n                remaining = self.pop_size - len(next_gen)\n                front_arr = np.array([ind.fitness.values for ind in front])\n                F_norm = (front_arr - z_min) / scale\n                \n                active_indices = list(range(len(front)))\n                \n                # SDE Step-wise density truncation\n                while len(active_indices) > remaining:\n                    active_F_norm = F_norm[active_indices]\n                    diff_front = active_F_norm[np.newaxis, :, :] - active_F_norm[:, np.newaxis, :]\n                    diff_front = np.maximum(0, diff_front)\n                    dists_front = np.sqrt(np.sum(diff_front ** 2, axis=2))\n                    np.fill_diagonal(dists_front, np.inf)\n                    \n                    sde_density = np.min(dists_front, axis=1)\n                    worst_idx = np.argmin(sde_density)\n                    del active_indices[worst_idx]\n                \n                selected_front = [front[i] for i in active_indices]\n                next_gen.extend(selected_front)\n                break\n                \n        return next_gen\n\n    def on_generation(self, gen: int, population: list):\n        pass",
4  "start_line": 297,
5  "end_line": 441,
6  "filename": "deap/custom_moea.py"
7}
Tool ResultStep 1
OK: Replaced lines 297..441 with 144 line(s) in deap/custom_moea.py. Editable range: 297–440.

[Current file: deap/custom_moea.py | editable: 297–440 | total: 589 lines]
   294| # ================================================================
   295| 
   296| 
   297  class CustomMOEA:
   298      """SDE-DE: Shift-Based Density Estimation with Differential Evolution."""
   299  
   300      def __init__(
   301          self,
   302          pop_size: int,
   303          n_obj: int,
   304          n_var: int,
   305          bounds: Tuple[float, float],
   306          cx_eta: float = 20.0,
   307          mut_eta: float = 20.0,
   308          mut_prob: Optional[float] = None,
   309      ):
   310          self.pop_size = pop_size
   311          self.n_obj = n_obj
   312          self.n_var = n_var
   313          self.bounds = bounds
   314          self.cx_eta = cx_eta
   315          self.mut_eta = mut_eta
   316          self.mut_prob = mut_prob if mut_prob is not None else 
AssistantStep 2test
Tool ResultStep 2
[Test #1] (2 tests remaining; call submit(n=1) to submit this result)

### zdt1 (scripts/zdt1.sh)
Training progress (last generations):
TRAIN_METRICS gen=120 hv=0.870131 igd=0.004339 spread=0.370017 front_size=100
TRAIN_METRICS gen=140 hv=0.870798 igd=0.004353 spread=0.359246 front_size=100
TRAIN_METRICS gen=160 hv=0.870716 igd=0.004020 spread=0.303221 front_size=100
TRAIN_METRICS gen=180 hv=0.870533 igd=0.004196 spread=0.339481 front_size=100
TRAIN_METRICS gen=200 hv=0.870868 igd=0.004286 spread=0.386009 front_size=100
Test results (zdt1):
  hv: 0.870868
  igd: 0.004286
  spread: 0.386009

### zdt3 (scripts/zdt3.sh)
Training progress (last generations):
TRAIN_METRICS gen=120 hv=1.324893 igd=0.005870 spread=0.682078 front_size=100
TRAIN_METRICS gen=140 hv=1.326212 igd=0.005766 spread=0.685178 front_size=100
TRAIN_METRICS gen=160 hv=1.325837 igd=0.006494 spread=0.732752 front_size=100
TRAIN_METRICS gen=180 hv=1.326230 igd=0.005822 spread=0.719554 front_size=100
TRAIN_METRICS gen=200 hv=
AssistantStep 3edit
Tool Input
1{
2  "filename": "deap/custom_moea.py",
3  "content": "class CustomMOEA:\n    \"\"\"SDE: Shift-Based Density Estimation.\"\"\"\n\n    def __init__(\n        self,\n        pop_size: int,\n        n_obj: int,\n        n_var: int,\n        bounds: Tuple[float, float],\n        cx_eta: float = 20.0,\n        mut_eta: float = 20.0,\n        mut_prob: Optional[float] = None,\n    ):\n        self.pop_size = pop_size\n        self.n_obj = n_obj\n        self.n_var = n_var\n        self.bounds = bounds\n        self.cx_eta = cx_eta\n        self.mut_eta = mut_eta\n        self.mut_prob = mut_prob if mut_prob is not None else 1.0 / n_var\n\n    def select(self, population: list, k: int) -> list:\n        # Assign rank and SDE density\n        fronts = tools.sortNondominated(population, len(population), first_front_only=False)\n        for rank, front in enumerate(fronts):\n            if len(front) <= 2:\n                for ind in front:\n                    ind._sde_density = float('inf')\n                    ind._rank = rank\n            else:\n                front_arr = np.array([ind.fitness.values for ind in front])\n                z_min = np.min(front_arr, axis=0)\n                z_max = np.max(front_arr, axis=0)\n                scale = z_max - z_min\n                scale[scale < 1e-12] = 1.0\n                F_norm = (front_arr - z_min) / scale\n                \n                diff_front = F_norm[np.newaxis, :, :] - F_norm[:, np.newaxis, :]\n                diff_front = np.maximum(0, diff_front)\n                dists_front = np.sqrt(np.sum(diff_front ** 2, axis=2))\n                np.fill_diagonal(dists_front, np.inf)\n                \n                sde_density = np.min(dists_front, axis=1)\n                for i, ind in enumerate(front):\n                    ind._sde_density = sde_density[i]\n                    ind._rank = rank\n\n        selected = []\n        for _ in range(k):\n            i1, i2 = random.sample(range(len(population)), 2)\n            ind1, ind2 = population[i1], population[i2]\n            \n            if ind1._rank < ind2._rank:\n                selected.append(deepcopy(ind1))\n            elif ind1._rank > ind2._rank:\n                selected.append(deepcopy(ind2))\n            else:\n                if ind1._sde_density > ind2._sde_density:\n                    selected.append(deepcopy(ind1))\n                else:\n                    selected.append(deepcopy(ind2))\n        return selected\n\n    def vary(self, parents: list) -> list:\n        offspring = [deepcopy(ind) for ind in parents]\n        lo, hi = self.bounds\n\n        for i in range(0, len(offspring) - 1, 2):\n            if random.random() < 0.9:\n                tools.cxSimulatedBinaryBounded(\n                    offspring[i], offspring[i + 1],\n                    eta=self.cx_eta, low=lo, up=hi,\n                )\n                del offspring[i].fitness.values\n                del offspring[i + 1].fitness.values\n\n        for ind in offspring:\n            if random.random() < 1.0:\n                tools.mutPolynomialBounded(\n                    ind, eta=self.mut_eta, low=lo, up=hi, indpb=self.mut_prob,\n                )\n                if not hasattr(ind, \"fitness\") or not ind.fitness.valid:\n                    try:\n                        del ind.fitness.values\n                    except AttributeError:\n                        pass\n        return offspring\n\n    def survive(self, population: list, offspring: list) -> list:\n        combined = population + offspring\n        fronts = tools.sortNondominated(combined, self.pop_size, first_front_only=False)\n        \n        combined_arr = np.array([ind.fitness.values for ind in combined])\n        z_min = np.min(combined_arr, axis=0)\n        z_max = np.max(combined_arr, axis=0)\n        scale = z_max - z_min\n        scale[scale < 1e-12] = 1.0\n\n        next_gen = []\n        for front in fronts:\n            if len(next_gen) + len(front) <= self.pop_size:\n                next_gen.extend(front)\n            else:\n                remaining = self.pop_size - len(next_gen)\n                front_arr = np.array([ind.fitness.values for ind in front])\n                F_norm = (front_arr - z_min) / scale\n                \n                active_indices = list(range(len(front)))\n                \n                while len(active_indices) > remaining:\n                    active_F_norm = F_norm[active_indices]\n                    diff_front = active_F_norm[np.newaxis, :, :] - active_F_norm[:, np.newaxis, :]\n                    diff_front = np.maximum(0, diff_front)\n                    dists_front = np.sqrt(np.sum(diff_front ** 2, axis=2))\n                    np.fill_diagonal(dists_front, np.inf)\n                    \n                    sde_density = np.min(dists_front, axis=1)\n                    worst_idx = np.argmin(sde_density)\n                    del active_indices[worst_idx]\n                \n                selected_front = [front[i] for i in active_indices]\n                next_gen.extend(selected_front)\n                break\n                \n        return next_gen\n\n    def on_generation(self, gen: int, population: list):\n        pass",
4  "start_line": 297,
5  "op": "replace",
6  "end_line": 440
7}
Tool ResultStep 3
OK: Replaced lines 297..440 with 128 line(s) in deap/custom_moea.py. Editable range: 297–424.

[Current file: deap/custom_moea.py | editable: 297–424 | total: 573 lines]
   294| # ================================================================
   295| 
   296| 
   297  class CustomMOEA:
   298      """SDE: Shift-Based Density Estimation."""
   299  
   300      def __init__(
   301          self,
   302          pop_size: int,
   303          n_obj: int,
   304          n_var: int,
   305          bounds: Tuple[float, float],
   306          cx_eta: float = 20.0,
   307          mut_eta: float = 20.0,
   308          mut_prob: Optional[float] = None,
   309      ):
   310          self.pop_size = pop_size
   311          self.n_obj = n_obj
   312          self.n_var = n_var
   313          self.bounds = bounds
   314          self.cx_eta = cx_eta
   315          self.mut_eta = mut_eta
   316          self.mut_prob = mut_prob if mut_prob is not None else 1.0 / n_var
   317  
   318    
AssistantStep 4test
Tool ResultStep 4
[Test #2] (1 test remaining; call submit(n=2) to submit this result)

### zdt1 (scripts/zdt1.sh)
Training progress (last generations):
TRAIN_METRICS gen=120 hv=0.862388 igd=0.007579 spread=0.395742 front_size=100
TRAIN_METRICS gen=140 hv=0.865814 igd=0.005624 spread=0.354986 front_size=100
TRAIN_METRICS gen=160 hv=0.866732 igd=0.005067 spread=0.352107 front_size=100
TRAIN_METRICS gen=180 hv=0.867996 igd=0.004650 spread=0.319493 front_size=100
TRAIN_METRICS gen=200 hv=0.869099 igd=0.004539 spread=0.347738 front_size=100
Test results (zdt1):
  hv: 0.869099
  igd: 0.004539
  spread: 0.347738

### zdt3 (scripts/zdt3.sh)
Training progress (last generations):
TRAIN_METRICS gen=120 hv=1.309961 igd=0.008402 spread=0.668550 front_size=100
TRAIN_METRICS gen=140 hv=1.317024 igd=0.007289 spread=0.691042 front_size=100
TRAIN_METRICS gen=160 hv=1.321535 igd=0.006548 spread=0.696177 front_size=100
TRAIN_METRICS gen=180 hv=1.324288 igd=0.006877 spread=0.713986 front_size=100
TRAIN_METRICS gen=200 hv=1