sympy/core/methods.py

   1 """ Defines default methods for unary and binary operations.
   2 """
   3
   4 from basic import Basic, cache_it
   5
   6 def _no_unary_operation(op, obj):
   7     return 'unary operation `%s` not defined for %s' % (op, obj.__class__.__name__)
   8 def _no_binary_operation(op, obj1, obj2):
   9     return 'binary operation `%s` not defined between %s and %s' \
  10            % (op, obj1.__class__.__name__, obj2.__class__.__name__)
  11
  12 class ArithMeths(object):
  13
  14     def __pos__(self):
  15         return self
  16     def __neg__(self):
  17         return Basic.Integer(-1) * self
  18     def __abs__(self):
  19         return Basic.abs(self)
  20     def __add__(self, other):
  21         return Basic.Add(self, other)
  22     def __radd__(self, other):
  23         return Basic.sympify(other).__add__(self)
  24     def __sub__(self, other):
  25         return self + (-Basic.sympify(other))
  26     def __rsub__(self, other):
  27         return Basic.sympify(other).__sub__(self)
  28     def __mul__(self, other):
  29         # FIXME this is a dirty hack. matrix should be ordinary SymPy object
  30         from sympy.matrices import Matrix
  31         if isinstance(other, Matrix): return NotImplemented
  32         return Basic.Mul(self, other)
  33     def __rmul__(self, other):
  34         return Basic.sympify(other).__mul__(self)
  35     def __pow__(self, other):
  36         return Basic.Pow(self, other)
  37     def __rpow__(self, other):
  38         return Basic.sympify(other).__pow__(self)
  39     def __div__(self, other):
  40         return self * (Basic.sympify(other) ** Basic.Integer(-1))
  41     def __truediv__(self, other):
  42         return self.__div__(other)
  43     def __rdiv__(self, other):
  44         return Basic.sympify(other).__div__(self)
  45     def __rtruediv__(self, other):
  46         return self.__rdiv__(other)
  47     def _eval_power(self, other):
  48         """ Evaluate Pow(self, other), return new object or None if
  49         no evaluation can be carried out. This method can be called
  50         only from Pow.__new__.
  51         """
  52         return None
  53
  54 class NoArithMeths(object):
  55
  56     def __pos__(self):
  57         raise TypeError, _no_unary_operation('+', self)
  58     def __neg__(self):
  59         raise TypeError, _no_unary_operation('-', self)
  60     def __add__(self, other):
  61         raise TypeError, _no_binary_operation('+', self, other)
  62     def __radd__(self, other):
  63         raise TypeError, _no_binary_operation('+', other, self)
  64     def __sub__(self, other):
  65         raise TypeError, _no_binary_operation('-', self, other)
  66     def __rsub__(self, other):
  67         raise TypeError, _no_binary_operation('-', other, self)
  68     def __mul__(self, other):
  69         raise TypeError, _no_binary_operation('*', self, other)
  70     def __rmul__(self, other):
  71         raise TypeError, _no_binary_operation('*', other, self)
  72     def __div__(self, other):
  73         raise TypeError, _no_binary_operation('/', self, other)
  74     def __rdiv__(self, other):
  75         raise TypeError, _no_binary_operation('/', other, self)
  76     def __pow__(self, other):
  77         raise TypeError, _no_binary_operation('**', self, other)
  78     def __rpow__(self, other):
  79         raise TypeError, _no_binary_operation('**', other, self)
  80     def _eval_power(self, other):
  81         return None
  82
  83 class RelMeths(object):
  84
  85     def __eq__(self, other):
  86         try:
  87             r = Basic.Equality(self, other)
  88         except ValueError, msg:
  89             # temporary workaround:
  90             print 'Failed to create Equality instance: %s, using repr equality test instead' % msg
  91             r = repr(self)==repr(other)
  92         return r
  93     def __ne__(self, other):
  94         return Basic.Unequality(self, other)
  95     def __lt__(self, other):
  96         #return Basic.sympify(other) > self
  97         return Basic.StrictInequality(self, other)
  98     def __gt__(self, other):
  99         return Basic.StrictInequality(other, self)
 100         #return Basic.sympify(other) < self
 101     def __le__(self, other):
 102         return Basic.Inequality(self, other)
 103     def __ge__(self, other):
 104         return Basic.sympify(other) <= self
 105
 106 class NoRelMeths(object):
 107
 108     def __eq__(self, other):
 109         return Basic.Equality(self, other)
 110     def __ne__(self, other):
 111         return Basic.Unequality(self, other)
 112     def __lt__(self, other):
 113         return hash(self) < hash(other)
 114         raise TypeError, _no_binary_operation('<', self, other)
 115     def __gt__(self, other):
 116         return hash(self) > hash(other)
 117         raise TypeError, _no_binary_operation('>', self, other)
 118     def __le__(self, other):
 119         raise TypeError, _no_binary_operation('<=', self, other)
 120     def __ge__(self, other):
 121         raise TypeError, _no_binary_operation('>=', self, other)