54 lines
1.3 KiB
Python
54 lines
1.3 KiB
Python
|
from . import rl
|
||
|
|
from .core import do_one, exhaust, switch
|
||
|
|
from .traverse import top_down
|
||
|
|
|
||
|
|
|
||
|
|
def subs(d, **kwargs):
|
||
|
|
""" Full simultaneous exact substitution.
|
||
|
|
|
||
|
|
Examples
|
||
|
|
========
|
||
|
|
|
||
|
|
>>> from sympy.strategies.tools import subs
|
||
|
|
>>> from sympy import Basic, S
|
||
|
|
>>> mapping = {S(1): S(4), S(4): S(1), Basic(S(5)): Basic(S(6), S(7))}
|
||
|
|
>>> expr = Basic(S(1), Basic(S(2), S(3)), Basic(S(4), Basic(S(5))))
|
||
|
|
>>> subs(mapping)(expr)
|
||
|
|
Basic(4, Basic(2, 3), Basic(1, Basic(6, 7)))
|
||
|
|
"""
|
||
|
|
if d:
|
||
|
|
return top_down(do_one(*map(rl.subs, *zip(*d.items()))), **kwargs)
|
||
|
|
else:
|
||
|
|
return lambda x: x
|
||
|
|
|
||
|
|
|
||
|
|
def canon(*rules, **kwargs):
|
||
|
|
""" Strategy for canonicalization.
|
||
|
|
|
||
|
|
Explanation
|
||
|
|
===========
|
||
|
|
|
||
|
|
Apply each rule in a bottom_up fashion through the tree.
|
||
|
|
Do each one in turn.
|
||
|
|
Keep doing this until there is no change.
|
||
|
|
"""
|
||
|
|
return exhaust(top_down(exhaust(do_one(*rules)), **kwargs))
|
||
|
|
|
||
|
|
|
||
|
|
def typed(ruletypes):
|
||
|
|
""" Apply rules based on the expression type
|
||
|
|
|
||
|
|
inputs:
|
||
|
|
ruletypes -- a dict mapping {Type: rule}
|
||
|
|
|
||
|
|
Examples
|
||
|
|
========
|
||
|
|
|
||
|
|
>>> from sympy.strategies import rm_id, typed
|
||
|
|
>>> from sympy import Add, Mul
|
||
|
|
>>> rm_zeros = rm_id(lambda x: x==0)
|
||
|
|
>>> rm_ones = rm_id(lambda x: x==1)
|
||
|
|
>>> remove_idents = typed({Add: rm_zeros, Mul: rm_ones})
|
||
|
|
"""
|
||
|
|
return switch(type, ruletypes)
|