97 lines
3.0 KiB
Python
97 lines
3.0 KiB
Python
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from sympy.core import Expr
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from sympy.core.decorators import call_highest_priority, _sympifyit
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from sympy.sets import ImageSet
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from sympy.sets.sets import set_add, set_sub, set_mul, set_div, set_pow, set_function
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class SetExpr(Expr):
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"""An expression that can take on values of a set.
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Examples
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========
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>>> from sympy import Interval, FiniteSet
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>>> from sympy.sets.setexpr import SetExpr
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>>> a = SetExpr(Interval(0, 5))
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>>> b = SetExpr(FiniteSet(1, 10))
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>>> (a + b).set
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Union(Interval(1, 6), Interval(10, 15))
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>>> (2*a + b).set
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Interval(1, 20)
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"""
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_op_priority = 11.0
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def __new__(cls, setarg):
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return Expr.__new__(cls, setarg)
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set = property(lambda self: self.args[0])
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def _latex(self, printer):
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return r"SetExpr\left({}\right)".format(printer._print(self.set))
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@_sympifyit('other', NotImplemented)
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@call_highest_priority('__radd__')
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def __add__(self, other):
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return _setexpr_apply_operation(set_add, self, other)
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@_sympifyit('other', NotImplemented)
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@call_highest_priority('__add__')
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def __radd__(self, other):
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return _setexpr_apply_operation(set_add, other, self)
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@_sympifyit('other', NotImplemented)
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@call_highest_priority('__rmul__')
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def __mul__(self, other):
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return _setexpr_apply_operation(set_mul, self, other)
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@_sympifyit('other', NotImplemented)
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@call_highest_priority('__mul__')
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def __rmul__(self, other):
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return _setexpr_apply_operation(set_mul, other, self)
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@_sympifyit('other', NotImplemented)
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@call_highest_priority('__rsub__')
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def __sub__(self, other):
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return _setexpr_apply_operation(set_sub, self, other)
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@_sympifyit('other', NotImplemented)
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@call_highest_priority('__sub__')
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def __rsub__(self, other):
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return _setexpr_apply_operation(set_sub, other, self)
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@_sympifyit('other', NotImplemented)
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@call_highest_priority('__rpow__')
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def __pow__(self, other):
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return _setexpr_apply_operation(set_pow, self, other)
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@_sympifyit('other', NotImplemented)
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@call_highest_priority('__pow__')
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def __rpow__(self, other):
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return _setexpr_apply_operation(set_pow, other, self)
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@_sympifyit('other', NotImplemented)
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@call_highest_priority('__rtruediv__')
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def __truediv__(self, other):
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return _setexpr_apply_operation(set_div, self, other)
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@_sympifyit('other', NotImplemented)
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@call_highest_priority('__truediv__')
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def __rtruediv__(self, other):
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return _setexpr_apply_operation(set_div, other, self)
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def _eval_func(self, func):
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# TODO: this could be implemented straight into `imageset`:
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res = set_function(func, self.set)
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if res is None:
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return SetExpr(ImageSet(func, self.set))
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return SetExpr(res)
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def _setexpr_apply_operation(op, x, y):
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if isinstance(x, SetExpr):
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x = x.set
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if isinstance(y, SetExpr):
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y = y.set
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out = op(x, y)
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return SetExpr(out)
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