measurements.py

   1 # For licensing info see the included LICENSE file
   2 #
   3 # Josef Moudrik, <J dot Moudrik at standard google mail ending>, 2012
   4
   5 import math
   6
   7 from number import Number
   8
   9 def avg(l):
  10     assert len(l)
  11     return sum(l) / float(len(l))
  12
  13 class MethodAnalyzer:
  14     def __init__(self):
  15         self.method_data = {}
  16         self.method_avg_sdsq = {}
  17
  18     def addMeasurement(self, m):
  19         assert m.method
  20         l = self.method_data.get(m.method, [])
  21         l.append( m.computeStats() )
  22         self.method_data[m.method] = l
  23
  24     def computeStats(self, verbose=False):
  25         for method, l in self.method_data.iteritems():
  26             avg_sdsq = avg( [ t[2] for t in l ] )
  27             min_sdsq = min( t[2] for t in l )
  28             max_sdsq = max( t[2] for t in l )
  29
  30             self.method_avg_sdsq[method] = avg_sdsq
  31             if verbose:
  32                 print method
  33                 print "min =", min_sdsq
  34                 print "avg =", avg_sdsq
  35                 print "max =", max_sdsq
  36
  37 class M:
  38     def __init__(self, name, ms, method=None, units=None, precise=False):
  39         if units == None:
  40             units = {'m':1}
  41
  42         if precise:
  43             assert len(ms) == 1
  44
  45         self.name = name
  46         self.ms = map(float, ms)
  47         #self.ms = ms
  48         self.method = method
  49         self.units = units
  50         self.precise = precise
  51
  52     def computeStats(self):
  53         n = len(self.ms)
  54         mean = avg(self.ms)
  55         # delime takhle kvuli nevychylenymu odhadu
  56         sdsq = sum((x - mean)**2 for x in self.ms) / ( (n - 1) if n > 1 else 1 )
  57
  58         return (n, mean, sdsq)
  59
  60     def toNumber(self, method_resolution=None, method_analyzer=None):
  61         if self.precise:
  62             return Number(self.ms[0], units=self.units, string=self.name)
  63
  64         n, mean, sdsq = self.computeStats()
  65         if self.method:
  66             if method_analyzer:
  67                 mavg = method_analyzer.method_avg_sdsq[self.method]
  68                 if sdsq < mavg:
  69                     sdsq = mavg
  70
  71             # the more measurements, the better
  72             sdsq /= n
  73
  74             if method_resolution:
  75                 # add the resolution of the method
  76                 sdsq += method_resolution[self.method] ** 2
  77
  78         return Number(mean, sdsq=sdsq, units=self.units, string=self.name)