sympycore/calculus/constants.py

   1 #
   2 # Created January 2008 by Pearu Peterson
   3 #
   4 """ Provides Constant class.
   5 """
   6 __docformat__ = "restructuredtext"
   7 __all__ = ['Constant', 'const_pi', 'const_E', 'const_gamma']
   8
   9 from ..core import classes
  10 from ..utils import SYMBOL, NUMBER
  11 from ..arithmetic.evalf import evalf
  12 from ..arithmetic import mpmath, setdps
  13
  14 class Constant(str):
  15
  16     def __repr__(self):
  17         return '%s(%r)' % (self.__class__.__name__, str(self))
  18
  19     def evalf(self, n=None):
  20         if n:
  21             setdps(n)
  22         if self == 'pi':
  23             return +mpmath.pi
  24         if self == 'E':
  25             return +mpmath.e
  26         if self == 'gamma':
  27             return +mpmath.euler
  28         raise NotImplementedError('%s(%r).evalf'
  29                                   % (self.__class__.__name__, self))
  30
  31     def as_algebra(self, cls):
  32         if cls is classes.Calculus:
  33             return cls.Symbol(self)
  34         return cls.convert(self)
  35
  36     def get_direction(self):
  37         if self in ['pi', 'E']:
  38             return 1
  39         return NotImplemented
  40
  41     @property
  42     def is_bounded(self):
  43         if self in ['pi', 'E']:
  44             return True
  45         return None
  46
  47 const_pi = Constant('pi')
  48 const_E = Constant('E')
  49 const_gamma = Constant('gamma')