Status: Accepted
Owner: ----
Labels: Type-Defect Priority-High
New issue 1527 by ondrej.certik: bug in the printer (function + subs)
http://code.google.com/p/sympy/issues/detail?id=1527
In [1]: F = Function('F')
In [2]: x, y, t = symbols('x y t')
In [3]: a = Symbol('a', Real=True)
In [4]: eq = Derivative(F(x, t), x)
In [5]: eq
Out[5]:
d
──(F(x, t))
dx
In [6]: pat = -33*t*x + F(x + exp(-t))
In [7]: pat
Out[7]:
⎛ -t⎞
-33⋅t⋅x + F⎝x + ℯ ⎠
In [8]: sub = eq.subs(F(x, t), pat)
In [9]: sub
Out[9]:
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
/home/ondrej/repos/sympy/<ipython console> in <module>()
/home/ondrej/usr/lib/python/IPython/Prompts.pyc in __call__(self, arg)
550
551 # and now call a possibly user-defined print mechanism
--> 552 manipulated_val = self.display(arg)
553
554 # user display hooks can change the variable to be
stored in
/home/ondrej/usr/lib/python/IPython/Prompts.pyc in _display(self, arg)
576 return IPython.generics.result_display(arg)
577 except TryNext:
--> 578 return self.shell.hooks.result_display(arg)
579
580 # Assign the default display method:
/home/ondrej/usr/lib/python/IPython/hooks.pyc in __call__(self, *args, **kw)
137 #print "prio",prio,"cmd",cmd #dbg
138 try:
--> 139 ret = cmd(*args, **kw)
140 return ret
141 except ipapi.TryNext, exc:
/home/ondrej/repos/sympy/sympy/interactive/__init__.pyc in
result_display(self, arg)
24 """
25 if self.rc.pprint:
---> 26 out = stringify_func(arg)
27
28 if '\n' in out:
/home/ondrej/repos/sympy/<input> in <lambda>(arg)
/home/ondrej/repos/sympy/sympy/printing/pretty/pretty.pyc in pretty(expr,
profile, **kargs)
610 try:
611 pp = PrettyPrinter(profile)
--> 612 return pp.doprint(expr)
613 finally:
614 pretty_use_unicode(uflag)
/home/ondrej/repos/sympy/sympy/printing/pretty/pretty.pyc in doprint(self,
expr)
29
30 def doprint(self, expr):
---> 31 return self._print(expr).render(**self._settings)
32
33 # empty op so _print(stringPict) returns the same
/home/ondrej/repos/sympy/sympy/printing/printer.pyc in _print(self, expr,
*args)
212 printmethod = '_print_' + cls.__name__
213 if hasattr(self, printmethod):
--> 214 res = getattr(self, printmethod)(expr, *args)
215 if res is None:
216 raise RuntimeError("Printing method '%s'
did return None"%\
/home/ondrej/repos/sympy/sympy/printing/pretty/pretty.pyc in
_print_Add(self, sum)
401 def _print_Add(self, sum):
402 args = list(sum.args)
--> 403 args.sort(Basic._compare_pretty)
404 pforms = []
405 for x in args:
/home/ondrej/repos/sympy/sympy/core/basic.pyc in _compare_pretty(a, b)
531 # because 1 = x^0, but 0 2 3 4 ... = x^1
532 p1, p2, p3 = Wild("p1"), Wild("p2"), Wild("p3")
--> 533 r_a = a.match(p1 * p2**p3)
534 r_b = b.match(p1 * p2**p3)
535 if r_a is not None and r_b is not None:
/home/ondrej/repos/sympy/sympy/core/basic.pyc in match(self, pattern)
1432 """
1433 pattern = sympify(pattern)
-> 1434 return pattern.matches(self, {})
1435
1436 def solve4linearsymbol(eqn, rhs, symbols = None):
/home/ondrej/repos/sympy/sympy/core/mul.pyc in matches(pattern, expr,
repl_dict, evaluate)
549 expr = sympify(expr)
550 if pattern.is_commutative and expr.is_commutative:
--> 551 return AssocOp._matches_commutative(pattern, expr,
repl_dict, evaluate)
552 # todo for commutative parts, until then use the default
matches method for non-commutative products
553 return Basic.matches(pattern, expr, repl_dict, evaluate)
/home/ondrej/repos/sympy/sympy/core/operations.pyc in
_matches_commutative(pattern, expr, repl_dict, evaluate)
134 d1 = w.matches(last_op, repl_dict)
135 if d1 is not None:
--> 136 d2 = pattern.matches(expr, d1, evaluate=True)
137 if d2 is not None:
138 return d2
/home/ondrej/repos/sympy/sympy/core/mul.pyc in matches(pattern, expr,
repl_dict, evaluate)
549 expr = sympify(expr)
550 if pattern.is_commutative and expr.is_commutative:
--> 551 return AssocOp._matches_commutative(pattern, expr,
repl_dict, evaluate)
552 # todo for commutative parts, until then use the default
matches method for non-commutative products
553 return Basic.matches(pattern, expr, repl_dict, evaluate)
/home/ondrej/repos/sympy/sympy/core/operations.pyc in
_matches_commutative(pattern, expr, repl_dict, evaluate)
94 pat = pattern
95 for old,new in repl_dict.items():
---> 96 pat = pat.subs(old, new)
97 if pat != pattern:
98 return pat.matches(expr, repl_dict)
/home/ondrej/repos/sympy/sympy/core/basic.pyc in subs(self, *args)
1037 elif len(args) == 2:
1038 old, new = args
-> 1039 return self._subs_old_new(old, new)
1040 else:
1041 raise TypeError("subs accepts either 1 or 2 arguments")
/home/ondrej/repos/sympy/sympy/core/cache.pyc in wrapper(*args, **kw_args)
83 except KeyError:
84 pass
---> 85 func_cache_it_cache[k] = r = func(*args, **kw_args)
86 return r
87
/home/ondrej/repos/sympy/sympy/core/basic.pyc in _subs_old_new(self, old,
new)
1046 old = sympify(old)
1047 new = sympify(new)
-> 1048 return self._eval_subs(old, new)
1049
1050 def _eval_subs(self, old, new):
/home/ondrej/repos/sympy/sympy/core/mul.pyc in _eval_subs(self, old, new)
752 ret_set = self_set - old_set
753 return Mul(new, coeff_self/coeff_old,
*[s._eval_subs(old, new) for s in ret_set])
--> 754 return self.__class__(*[s._eval_subs(old, new) for s in
self.args])
755
756 def _eval_nseries(self, x, x0, n):
/home/ondrej/repos/sympy/sympy/core/power.pyc in _eval_subs(self, old, new)
213 coeff2,terms2 = (self.exp *
C.log(self.base)).as_coeff_terms()
214 if terms1==terms2: return new ** (coeff1/coeff2) #
(x**(2*y)).subs(exp(3*y*log(x)),z) -> z**(2/3*y)
--> 215 return self.base._eval_subs(old, new) **
self.exp._eval_subs(old, new)
216
217 def as_powers_dict(self):
/home/ondrej/repos/sympy/sympy/core/function.pyc in _eval_subs(self, old,
new)
617 if self==old:
618 return new
--> 619 return Derivative(*map(lambda x: x._eval_subs(old, new),
self.args), **{'evaluate': True})
620
621 def matches(pattern, expr, repl_dict={}, evaluate=False):
/home/ondrej/repos/sympy/sympy/core/function.pyc in __new__(cls, expr,
*symbols, **assumptions)
576 s = sympify(s)
577 if not isinstance(s, Symbol):
--> 578 raise ValueError('Invalid literal: %s is not a
valid variable' % s)
579 if not expr.has(s):
580 return S.Zero
ValueError: Invalid literal: x + exp(-t) is not a valid variable
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