Coverage for /usr/lib/python3/dist-packages/sympy/strategies/tools.py: 64%

1from . import rl 

2from .core import do_one, exhaust, switch 

3from .traverse import top_down 

4 

5 

6def subs(d, **kwargs): 

7 """ Full simultaneous exact substitution. 

8 

9 Examples 

10 ======== 

11 

12 >>> from sympy.strategies.tools import subs 

13 >>> from sympy import Basic, S 

14 >>> mapping = {S(1): S(4), S(4): S(1), Basic(S(5)): Basic(S(6), S(7))} 

15 >>> expr = Basic(S(1), Basic(S(2), S(3)), Basic(S(4), Basic(S(5)))) 

16 >>> subs(mapping)(expr) 

17 Basic(4, Basic(2, 3), Basic(1, Basic(6, 7))) 

18 """ 

19 if d: 

20 return top_down(do_one(*map(rl.subs, *zip(*d.items()))), **kwargs) 

21 else: 

22 return lambda x: x 

23 

24 

25def canon(*rules, **kwargs): 

26 """ Strategy for canonicalization. 

27 

28 Explanation 

29 =========== 

30 

31 Apply each rule in a bottom_up fashion through the tree. 

32 Do each one in turn. 

33 Keep doing this until there is no change. 

34 """ 

35 return exhaust(top_down(exhaust(do_one(*rules)), **kwargs)) 

36 

37 

38def typed(ruletypes): 

39 """ Apply rules based on the expression type 

40 

41 inputs: 

42 ruletypes -- a dict mapping {Type: rule} 

43 

44 Examples 

45 ======== 

46 

47 >>> from sympy.strategies import rm_id, typed 

48 >>> from sympy import Add, Mul 

49 >>> rm_zeros = rm_id(lambda x: x==0) 

50 >>> rm_ones = rm_id(lambda x: x==1) 

51 >>> remove_idents = typed({Add: rm_zeros, Mul: rm_ones}) 

52 """ 

53 return switch(type, ruletypes)