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# Description
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# Compute and produce statistics


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# Public Functions
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def stats(stream):
    min_inversion = -1
    max_inversion = -1
    sum_inversions = 0
    num_inversions = 0
    for record in stream:
        if record.type_name == 'inversion_end':
            length = record.job.inversion_end - record.job.inversion_start
            if length > 0:
                num_inversions += 1
                if length > max_inversion:
                    max_inversion = length
                if length < min_inversion or min_inversion == -1:
                    min_inversion = length
                sum_inversions += length
        yield record
    if num_inversions > 0:
        avg_inversion = int(sum_inversions / num_inversions)
    else:
        avg_inversion = 0
    class Obj(): pass
    rec = Obj()
    rec.record_type = "meta"
    rec.type_name = "stats"
    rec.num_inversions = num_inversions 
    rec.min_inversion = min_inversion
    rec.max_inversion = max_inversion
    rec.avg_inversion = avg_inversion
    yield rec