SymPy –> Sage conversion¶
The file consists of _sage_() methods that are added lazily to
the respective SymPy objects. Any call of the _sympy_() method
of a symbolic expression will trigger the addition. See
sage.symbolic.expression_conversion.SymPyConverter for the
conversion to SymPy.
Only Function objects where the names differ need their own _sage()_
method. There are several functions with differing name that have an alias
in Sage that is the same as the name in SymPy, so no explicit translation
is needed for them:
sage: from sympy import Symbol, Si, Ci, Shi, Chi, sign
sage: sx = Symbol('x')
sage: assert sin_integral(x)._sympy_() == Si(sx)
sage: assert sin_integral(x) == Si(sx)._sage_()
sage: assert sinh_integral(x)._sympy_() == Shi(sx)
sage: assert sinh_integral(x) == Shi(sx)._sage_()
sage: assert cos_integral(x)._sympy_() == Ci(sx)
sage: assert cos_integral(x) == Ci(sx)._sage_()
sage: assert cosh_integral(x)._sympy_() == Chi(sx)
sage: assert cosh_integral(x) == Chi(sx)._sage_()
sage: assert sgn(x)._sympy_() == sign(sx)
sage: assert sgn(x) == sign(sx)._sage_()
>>> from sage.all import *
>>> from sympy import Symbol, Si, Ci, Shi, Chi, sign
>>> sx = Symbol('x')
>>> assert sin_integral(x)._sympy_() == Si(sx)
>>> assert sin_integral(x) == Si(sx)._sage_()
>>> assert sinh_integral(x)._sympy_() == Shi(sx)
>>> assert sinh_integral(x) == Shi(sx)._sage_()
>>> assert cos_integral(x)._sympy_() == Ci(sx)
>>> assert cos_integral(x) == Ci(sx)._sage_()
>>> assert cosh_integral(x)._sympy_() == Chi(sx)
>>> assert cosh_integral(x) == Chi(sx)._sage_()
>>> assert sgn(x)._sympy_() == sign(sx)
>>> assert sgn(x) == sign(sx)._sage_()
AUTHORS:
- Ralf Stephan (2017-10) 
- class sage.interfaces.sympy.UndefSageHelper[source]¶
- Bases: - object- Helper class to convert sympy function objects to sage functions - EXAMPLES: - sage: from sympy import Function sage: f = function('f') sage: F = Function('f') sage: assert f._sympy_() == F sage: assert f == F._sage_() - >>> from sage.all import * >>> from sympy import Function >>> f = function('f') >>> F = Function('f') >>> assert f._sympy_() == F >>> assert f == F._sage_() 
- sage.interfaces.sympy.check_expression(expr, var_symbols, only_from_sympy=False)[source]¶
- Do - eval(expr)both in Sage and SymPy and other checks.- EXAMPLES: - sage: from sage.interfaces.sympy import check_expression sage: check_expression("1.123*x", "x") - >>> from sage.all import * >>> from sage.interfaces.sympy import check_expression >>> check_expression("1.123*x", "x") 
- sage.interfaces.sympy.sympy_init(*args, **kwargs)[source]¶
- Add - _sage_()methods to SymPy objects where needed.- This gets called with every call to - Expression._sympy_()so there is only need to call it if you bypass- _sympy_()to create SymPy objects. Note that SymPy objects have- _sage_()methods hard installed but having them inside Sage as one file makes them easier to maintain for Sage developers.- EXAMPLES: - sage: from sage.interfaces.sympy import sympy_init sage: from sympy import Symbol, Abs sage: sympy_init() sage: assert abs(x) == Abs(Symbol('x'))._sage_() - >>> from sage.all import * >>> from sage.interfaces.sympy import sympy_init >>> from sympy import Symbol, Abs >>> sympy_init() >>> assert abs(x) == Abs(Symbol('x'))._sage_()