Re: Issue 240 in mpmath: left scalar multiplication of an interval matrix fails

[mpm...@googlecode.com]

Comment #1 on issue 240 by talc...@gmail.com: left scalar multiplication of
an interval matrix fails
http://code.google.com/p/mpmath/issues/detail?id=240

I forgot to mention, right scalar multiplication works strangely enough.

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[mpm...@googlecode.com]

Status: New
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New issue 240 by talc...@gmail.com: left scalar multiplication of an

interval matrix fails
http://code.google.com/p/mpmath/issues/detail?id=240

What steps will reproduce the problem?
1. Define an interval matrix
>>> A = iv.matrix([[1,2],[3,4]])
2. Left multiply the matrix by a scalar interval
>>> iv.mpf(2)*A

What is the expected output? What do you see instead?
It should give the double of the matrix, but instead it fails and prints
the following stack trace:

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python2.7/site-packages/mpmath/ctx_iv.py", line 230, in
lop_real
if not isinstance(t, ctx._types): t = ctx.convert(t)
File "/usr/lib/python2.7/site-packages/mpmath/ctx_iv.py", line 415, in
convert
assert mpf_le(a, b), "endpoints must be properly ordered"
File "/usr/lib/python2.7/site-packages/mpmath/libmp/libmpf.py", line 608,
in mpf_le
return mpf_cmp(s, t) <= 0
File "/usr/lib/python2.7/site-packages/mpmath/libmp/libmpf.py", line 555,
in mpf_cmp
ssign, sman, sexp, sbc = s
TypeError: 'NoneType' object is not iterable

What version of the product are you using? On what operating system?
Fedora 18, python 2.7.3, mpmath 0.17

Please provide any additional information below.