anchor.diff:      P = 0.5 * math:erfc(Bucket / W),
       BucketP = P - PrevP,
       if
  -        TargetP =< BucketP ->
  +        BucketP < TargetP ->
               check_histogram(
                 W, Rounds, StdDevs, Histogram, TargetP,
                 Bucket - 1, PrevBucket, PrevP, N);
  
positive.code:             UpperLimit = ceil(Exp + Threshold),
              if
                  N < LowerLimit; UpperLimit < N ->
                      [#{bucket => {Bucket, PrevBucket}, n => N, exp => Exp,
                         lower => LowerLimit, upper => UpperLimit} |
                       check_histogram(
                         W, Rounds, StdDevs, Histogram, TargetP,
  
negative.code:     array:set(Bucket, array:get(Bucket, Array) + 1, Array).
  
  check_histogram(W, Rounds, StdDevs, Histogram, Buckets) ->
      TargetP = 0.5 * math:erfc(Buckets / W),
      P = 0.0,
      N = 0,
  