Status: New
Owner: ----
Labels: Type-Defect Priority-Medium
New issue 1515 by indrek.mandre: caching does not distinct ints and longs
http://code.google.com/p/sympy/issues/detail?id=1515
Sympy caches Integer-s. But this caching does not
distinct ints and longs. But some code inside
sympy seems to require ints.
For example here number '3' has been promoted to
long, somehow, and matrix code fails:
from sympy import *
x, y, t = symbols('xyt')
P1 = Poly(sympify('a3*t**3+a2*t**2+a1*t+a0-x'),t)
print type(sympify(3).p)
print type(P1.degree)
zeros(P1.degree)
with output:
<type 'long'>
<type 'long'>
Traceback (most recent call last):
File "bug.py", line 7, in <module>
zeros(P1.degree)
File "/home/soft/sympy-0.6.5.beta2/sympy/matrices/matrices.py", line
1517, in zeros
n, m = _dims_to_nm( dims )
File "/home/soft/sympy-0.6.5.beta2/sympy/matrices/matrices.py", line 38,
in _dims_to_nm
raise ValueError("Matrix dimensions should positive integers!")
ValueError: Matrix dimensions should positive integers!
This inconsistency is very bad. Either use only ints or only longs.
This kind of thing is also hidden and one can easily experience
strange behaviour when writing more serious applications on their
own. Hidden promotion of types will cost time and space.
A thumbed down example of the inconsistency:
sympify(3L)
sympify(4)
print type(sympify(3).p)
print type(sympify(4).p)
with output:
<type 'long'>
<type 'int'>
There may be 3 bugs here:
a) the first sympify somehow turns 3 into long
b) the matrix code does not accept long
c) int/long inconsistency
I guess a and b can be fixed trivially, but c is a fundamental issue.
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