Larry,
On Fri, Sep 7, 2012 at 2:50 PM, Larry Wigton <lbw9...@aol.com> wrote:
>
>
> On Thursday, September 6, 2012 6:26:38 PM UTC-7, smichr wrote:
>>
>> On Fri, Sep 7, 2012 at 1:40 AM, Larry Wigton <lbw...@aol.com> wrote:
>> > Python code using cse from sympy:
>> >
>> > from sympy import *
>> > x=Symbol('x')
>> > y=Symbol('y')
>> > eq1 = 5*x**3*y**2 + y**3
>> > eq2 = 4*x**2*y**3 + y**2
>> > eq = [eq1,eq2]
>> > print eq
>> > (red,rep) = cse(eq)
>> > print red
>> > print rep
>> > eq = [eq2,eq1]
>> > print eq
>> > (red,rep) = cse(eq)
>> > print red
>> > print rep
>> >
>> > ***********************************************
>> >
>> > Output from the code:
>> >
>> > [5*x**3*y**2 + y**3, 4*x**2*y**3 + y**2]
>> > [(x0, y**3), (x1, x0**(2/3))]
>> > [5*x**3*x1 + x0, 4*x**2*x0 + x1]
>> >
>> > [4*x**2*y**3 + y**2, 5*x**3*y**2 + y**3]
>> > [(x0, y**2), (x1, x0**(3/2))]
>> > [4*x**2*x1 + x0, 5*x**3*x0 + x1]
>> >
>> > **********************************************
>>
>> Current master gives
>>
>> [5*x**3*y**2 + y**3, 4*x**2*y**3 + y**2]
>> [(x0, y**2)]
>> [x0*(5*x**3 + y), x0*(4*x**2*y + 1)]
>> [4*x**2*y**3 + y**2, 5*x**3*y**2 + y**3]
>> [(x0, y**2)]
>> [x0*(4*x**2*y + 1), x0*(5*x**3 + y)]
>>
>> googling sympy bleeding edge if you would like to get the most
>> up-to-date (and soon to be released) 0.7.2 version.
>
>
>
>
> Thank you for telling me about the Bleeding edge version of sympy.
>
> Unfortunately it does not work for case which worked before.
>
> Test case for bleeding edge version of sympy:
>
> **************************************************
>
> pg00 = Symbol('pg00')
> pg01 = Symbol('pg01')
> eq1 = sympify(pg01**2/pg00**2)
> eq2 = sympify(1.0 - 2*pg01/pg00)
> eq3 = sympify(pg01*(1.0 - pg01/pg00))
> eq = [eq1,eq2,eq3]
>
> print eq
> (red,rep) = cse(eq)
> print red
> print rep
>
> ********************************************************
>
> Output from code:
>
> [pg01**2/pg00**2, 1.0 - 2*pg01/pg00, pg01*(1.0 - pg01/pg00)]
> Traceback (most recent call last):
> File "mytest3.py", line 12, in <module>
> (red,rep) = cse(eq)
> File "/acct/lbw9902/gitstuff/sympy/sympy/simplify/cse_main.py", line 313,
> in cse
> reduced_exprs[j] = update(expr)
> File "/acct/lbw9902/gitstuff/sympy/sympy/simplify/cse_main.py", line 309,
> in <lambda>
> update = lambda x: x.subs(subtree, sym)
> File "/acct/lbw9902/gitstuff/sympy/sympy/core/basic.py", line 852, in subs
> rv = rv._subs(old, new)
> File "/acct/lbw9902/gitstuff/sympy/sympy/core/cache.py", line 88, in
> wrapper
> func_cache_it_cache[k] = r = func(*args, **kw_args)
> File "/acct/lbw9902/gitstuff/sympy/sympy/core/basic.py", line 951, in
> _subs
> rv = fallback(self, old, new)
> File "/acct/lbw9902/gitstuff/sympy/sympy/core/basic.py", line 938, in
> fallback
> arg = arg._subs(old, new, **hints)
> File "/acct/lbw9902/gitstuff/sympy/sympy/core/cache.py", line 88, in
> wrapper
> func_cache_it_cache[k] = r = func(*args, **kw_args)
> File "/acct/lbw9902/gitstuff/sympy/sympy/core/basic.py", line 949, in
> _subs
> rv = self._eval_subs(old, new)
> File "/acct/lbw9902/gitstuff/sympy/sympy/core/mul.py", line 1276, in
> _eval_subs
> rat.append(ndiv(c_e, old_e))
> File "/acct/lbw9902/gitstuff/sympy/sympy/core/mul.py", line 1186, in ndiv
> if not b.q % a.q or not a.q % b.q:
> AttributeError: 'Infinity' object has no attribute 'q'
>
> **************************************************************
>
> Output from sympy 7.1
>
> [pg01**2/pg00**2, 1.0 - 2*pg01/pg00, pg01*(1.0 - pg01/pg00)]
> [(x0, 1/pg00), (x1, pg01*x0)]
> [x1**2, -2*x1 + 1.0, pg01*(-x1 + 1.0)]
>
> ***********************************************************
>
> So it looks like bleeding edge version of sympy still needs some work.
This looks like a regression. Thanks for posting it.
If you want to help us debug it, just use "git bisect" to figure out a
patch that broke this.
Then it should be possible to see how to fix this.
Ondrej
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