[SciPy-User] loadmat/savemat sparse with umfpack problem
Robin
robince@gmail....
Mon Dec 14 10:54:06 CST 2009
On Mon, Dec 14, 2009 at 4:17 PM, Matthew Brett <matthew.brett@gmail.com> wrote:
> Hi,
>
>> Still not sure why though - in this simple example the indices do seem
>> to be sorted - the only change I can find from calling the
>> sorted_indices function is that after the WRITEABLE flag of .indices
>> is True (as it is originally) but on the loadmat'ed array WRITEABLE is
>> False.
>>
>> Could this be causing it? Is it a bug in loadmat - should the flag be
>> set differently? (I'm not sure what it does).
>
> Yes, that's strange. Do you see the same behavior for loadmat from scipy 0.7.1?
No, Python 2.6 with scipy 0.7.1 (through macports) doesn't seem to
have WRITEABLE False. I don't have umfpack in that installation to
check but I would guess it would work.
In [3]: scipy.__version__
Out[3]: '0.7.1'
In [4]: a.indices.flags
Out[4]:
C_CONTIGUOUS : True
F_CONTIGUOUS : True
OWNDATA : False
WRITEABLE : True
ALIGNED : True
UPDATEIFCOPY : False
In [6]: a2.indices.flags
Out[6]:
C_CONTIGUOUS : True
F_CONTIGUOUS : True
OWNDATA : False
WRITEABLE : True
ALIGNED : True
UPDATEIFCOPY : False
The environment where is happens is python 2.5.4, scipy '0.8.0.dev6136'
But it is not limited to sparse, everything seems to be loaded with
writeable false (I'm not sure if this would be causing the problem
with umfpack or if it could cause other problems):
In [61]: a = eye(3)
In [62]: a.flags
Out[62]:
C_CONTIGUOUS : True
F_CONTIGUOUS : False
OWNDATA : True
WRITEABLE : True
ALIGNED : True
UPDATEIFCOPY : False
In [63]: savemat('test',{'a':a})
In [64]: a2 = loadmat('test')['a']
In [65]: a2.flags
Out[65]:
C_CONTIGUOUS : False
F_CONTIGUOUS : True
OWNDATA : False
WRITEABLE : False
ALIGNED : False
UPDATEIFCOPY : False
Cheers
Robin
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