"""geometric_mean — Geometric mean of positive values."""

import math
import numpy as np


def geometric_mean(values: list[float]) -> float:
    """Return the geometric mean of the positive elements in values.

    Filters out non-positive numbers before computing exp(mean(log(x))).
    Returns math.nan if there are no positive values.

    Args:
        values: List of numeric values (non-positive elements are ignored).

    Returns:
        Geometric mean as float, or math.nan if no positive values exist.
    """
    positives = [v for v in values if v > 0]
    if not positives:
        return math.nan
    arr = np.array(positives, dtype=float)
    return float(np.exp(np.mean(np.log(arr))))