#6424: One can no longer convert I=sqrt(-1) to sympy
-----------------------+----------------------------------------------------
Reporter: drkirkby | Owner: tbd
Type: defect | Status: new
Priority: major | Milestone: sage-4.1.1
Component: symbolics | Keywords:
Reviewer: | Author:
Merged: |
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Comment(by mvngu):
From this [http://groups.google.com/group/sage-
devel/browse_thread/thread/c484e5ccbc884998 sage-devel] thread by Ondrej
Certik:
Currently this fails:
sage: sympy.test("sympy/test_external/")
============================= test process starts
==============================
executable:
/home/ondrej/sage-4.1-sage.math.washington.edu-x86_64-Linux/local/bin/sage.bin
(2.6.2-final-0)
sympy/test_external/test_codegen_c_cc.py[5] .....
[OK]
sympy/test_external/test_numpy.py[19] ...................
[OK]
sympy/test_external/test_sage.py[13] .E...........
[FAIL]
[...]
File
"/home/ondrej/sage-4.1-sage.math.washington.edu-x86_64-Linux/local/lib/python2.6
/site-packages/sympy/core/sympify.py",
line 194, in _sympify
raise SympifyError("%r is NOT a valid SymPy expression" % (a,))
SympifyError: SympifyError: I is NOT a valid SymPy expression
=========== tests finished: 36 passed, 1 exceptions in 3.26 seconds
============
DO *NOT* COMMIT!
False
This patch fixes it:
diff -r ca1f31d6f6bf sage/symbolic/expression_conversions.py
--- a/sage/symbolic/expression_conversions.py Thu Jul 09 15:14:36 2009
-0700
+++ b/sage/symbolic/expression_conversions.py Mon Jul 13 16:57:22 2009
-0700
@@ -572,7 +572,7 @@
"""
import sympy
operator = arithmetic_operators[operator]
- ops = [self(a) for a in ex.operands()]
+ ops = [sympy.sympify(self(a)) for a in ex.operands()]
if operator == "+":
return sympy.Add(*ops)
elif operator == "*":
Now:
sage: sympy.test("sympy/test_external/")
============================= test process starts
==============================
executable:
/home/ondrej/sage-4.1-sage.math.washington.edu-x86_64-Linux/local/bin/sage.bin
(2.6.2-final-0)
sympy/test_external/test_codegen_c_cc.py[5] .....
[OK]
sympy/test_external/test_numpy.py[19] ...................
[OK]
sympy/test_external/test_sage.py[13] .............
[OK]
================== tests finished: 37 passed in 2.29 seconds
===================
True
I vaguely remember William run into this bug recently. It was caused
by switching to the new symbolic, the problem was that passing things
directly to Mul classes in sympy goes in the fast track and only
sympifies easy things like python ints. For Sage integers, a full
sympify must be called, which is what my patch does. The core of the
problem is in fact in sympy cache mechanism, which only does fast
track sympify for performance reasons, so the proper fix is to fix our
cache, which is exactly what we plan to do --- get rid of it,
hopefully by the end of the summer.
We are about to release a new sympy now, so the above patch makes all
sympy 0.6.6 tests pass.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/6424#comment:2>
Sage <http://sagemath.org/>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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