number.py

   1 # -*- coding: utf-8 -*-
   2
   3 import math
   4
   5 from exc import IncompatibleUnits
   6 import operators
   7
   8 def units_op(u1, u2, op):
   9     u = {}
  10     for k in u1.viewkeys() | u2.viewkeys():
  11         v1, v2 = u1.get(k, 0), u2.get(k, 0)
  12         v = op( v1, v2 )
  13         if v != 0:
  14             u[k] = v
  15     return u
  16
  17 def units_diff(u1, u2):
  18     return units_op(u1, u2, lambda x, y : x - y)
  19
  20 def units_join(u1, u2):
  21     return units_op(u1, u2, lambda x, y : x + y)
  22
  23 class Number:
  24     def __init__(self, value, sdsq=0, units=None, string='', parents=None):
  25         if units == None:
  26             units = {}
  27
  28         self.value = float(value)
  29         self.sdsq = sdsq
  30         self.units = units
  31         self.string = string
  32         self.parents = parents
  33
  34     def __add__(self, other):
  35         return operators.Plus()((self, other))
  36
  37     def __sub__(self, other):
  38         return operators.Minus()((self, other))
  39
  40     def __mul__(self, other):
  41         return operators.Mult()((self, other))
  42
  43     def __rmul__(self, other):
  44         assert isinstance(other, int) or isinstance(other, float)
  45
  46         return operators.Times(other)((self,))
  47
  48     def __div__(self, other):
  49         return operators.Div()((self, other))
  50
  51     def getDifference(self, other):
  52     # TODO lip??
  53         if self.getUnits() != other.getUnits():
  54             raise IncompatibleUnits
  55
  56         assert self.sdsq == 0
  57
  58         diff = abs(1.0 - other.getValue() / self.getValue())
  59
  60         op = other.getSdPerc()
  61         if diff < op:
  62             return op
  63
  64         return diff
  65
  66     def getValue(self):
  67         return self.value
  68
  69     def getSdSquare(self):
  70         return self.sdsq
  71
  72     def getSd(self):
  73         return math.sqrt(self.getSdSquare())
  74
  75     def getSdPerc(self):
  76         return self.getSd() / abs(self.getValue())
  77
  78     def getUnits(self):
  79         return self.units
  80
  81     def strUnits(self):
  82         l=[]
  83         for key in sorted(self.units.keys()):
  84             l.append(key)
  85             v = self.units[key]
  86             if v != 1:
  87                 l.append( '^%d'%(v,))
  88         return ''.join(l)
  89
  90     def longStr(self):
  91         return self.headStr() + " = " + str(self)
  92
  93     def headStr(self):
  94         return u'%.4f ± %.4f %s'%(self.getValue(), self.getSd(), self.strUnits())
  95
  96     def __str__(self):
  97         s = self.string
  98         if self.parents:
  99             s += "(%s)"%(', '.join(map(str, self.parents), ), )
 100         return s