Function cdf

src/compute-engine/numerics/distributions.ts:69–70

(k: number)

  // CDF(k) = P(X ≤ k) = I_{1−p}(n−k, k+1); the kernel is undefined at a=0,
  // so the k ≥ n endpoint (CDF = 1) is handled explicitly.
  const cdf = (k: number): number =>
    k >= n ? 1 : k < 0 ? 0 : betaRegularized(1 - p, n - k, k + 1);
  return discreteQuantile(cdf, prob, mean, stddev, 0, n, deadline);
}