/usr/share/pyshared/sympy/simplify/traversaltools.py is in python-sympy 0.7.1.rc1-3.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 | """Tools for applying functions to specified parts of expressions. """
from sympy.core import sympify
def use(expr, func, level=0, args=(), kwargs={}):
"""
Use ``func`` to transform ``expr`` at the given level.
Example
=======
>>> from sympy import use, expand
>>> from sympy.abc import x, y
>>> f = (x + y)**2*x + 1
>>> use(f, expand, level=2)
x*(x**2 + 2*x*y + y**2) + 1
>>> expand(f)
x**3 + 2*x**2*y + x*y**2 + 1
"""
def _use(expr, level):
if not level:
return func(expr, *args, **kwargs)
else:
if expr.is_Atom:
return expr
else:
level -= 1
_args = []
for arg in expr.args:
_args.append(_use(arg, level))
return expr.__class__(*_args)
return _use(sympify(expr), level)
|