1 # Copyright (c) 2018 Cisco and/or its affiliates.
2 # Licensed under the Apache License, Version 2.0 (the "License");
3 # you may not use this file except in compliance with the License.
4 # You may obtain a copy of the License at:
6 # http://www.apache.org/licenses/LICENSE-2.0
8 # Unless required by applicable law or agreed to in writing, software
9 # distributed under the License is distributed on an "AS IS" BASIS,
10 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 # See the License for the specific language governing permissions and
12 # limitations under the License.
16 from AvgStdevMetadata import AvgStdevMetadata
19 class AvgStdevMetadataFactory(object):
20 """Class factory which creates avg,stdev metadata from data."""
23 def from_data(values):
24 """Return new metadata object fitting the values.
26 :param values: Run values to be processed.
27 :type values: Iterable of float or of AvgStdevMetadata
28 :returns: The metadata matching the values.
29 :rtype: AvgStdevMetadata
35 if isinstance(value, AvgStdevMetadata):
37 sum_1 += value.avg * value.size
38 sum_2 += value.stdev * value.stdev * value.size
39 sum_2 += value.avg * value.avg * value.size
40 else: # The value is assumed to be float.
43 sum_2 += value * value
45 return AvgStdevMetadata()
47 stdev = math.sqrt(sum_2 / sum_0 - avg * avg)
48 ret_obj = AvgStdevMetadata(size=sum_0, avg=avg, stdev=stdev)