Method _update_island_best_program

data/database.py:1224–1274

Update the best program tracking for a specific island Args: program: Program to consider as the new best for the island island_idx: Island index

(self, program: Program, island_idx: int)

                logger.info(f"New best program {program.id} replaces {old_id}")

    def _update_island_best_program(self, program: Program, island_idx: int) -> None:
        """
        Update the best program tracking for a specific island

        Args:
            program: Program to consider as the new best for the island
            island_idx: Island index
        """
        # Ensure island_idx is valid
        if island_idx >= len(self.island_best_programs):
            logger.warning(f"Invalid island index {island_idx}, skipping island best update")
            return

        # If island doesn't have a best program yet, this becomes the best
        current_island_best_id = self.island_best_programs[island_idx]
        if current_island_best_id is None:
            self.island_best_programs[island_idx] = program.id
            logger.debug(f"Set initial best program for island {island_idx} to {program.id}")
            return

        # Check if current best still exists
        if current_island_best_id not in self.programs:
            logger.warning(
                f"Island {island_idx} best program {current_island_best_id} no longer exists, updating to {program.id}"
            )
            self.island_best_programs[island_idx] = program.id
            return

        current_island_best = self.programs[current_island_best_id]

        # Update if the new program is better
        if self._is_better(program, current_island_best):
            old_id = current_island_best_id
            self.island_best_programs[island_idx] = program.id

            # Log the change
            if (
                "combined_score" in program.metrics
                and "combined_score" in current_island_best.metrics
            ):
                old_score = current_island_best.metrics["combined_score"]
                new_score = program.metrics["combined_score"]
                score_diff = new_score - old_score
                logger.debug(
                    f"Island {island_idx}: New best program {program.id} replaces {old_id} "
                    f"(combined_score: {old_score:.4f} → {new_score:.4f}, +{score_diff:.4f})"
                )
            else:
                logger.debug(
                    f"Island {island_idx}: New best program {program.id} replaces {old_id}"
                )

    def _sample_parent(self) -> Program:
        """