[SciPy-user] Bug in inversematrixcalculation for "scipy_core-0.8.4.win32-py2.3.exe"

Randewijk P-J <pjrandew@sun.ac.za> pjrandew at sun.ac.za
Thu Dec 15 01:45:23 CST 2005


Oops,

My platform is winXP, py2.3 using the following binaries: 

scipy_core-0.8.4.win32-py2.3.exe
and
scipy-0.4.3.win32-py2.3.exe

The "older" scipy_core binary file:
 
scipy_core-0.6.1.win32-py2.3.exe
and
scipy-0.4.3.win32-py2.3.exe

does works fine together...


> -----Original Message-----
> From: scipy-user-bounces at scipy.net 
> [mailto:scipy-user-bounces at scipy.net] On Behalf Of Randewijk 
> P-J <pjrandew at sun.ac.za>
> Sent: 15 December 2005 09:39
> To: SciPy Users List
> Subject: Re: [SciPy-user] Bug in inversematrixcalculation for 
> "scipy_core-0.8.4.win32-py2.3.exe"
> 
> 
> Dear Travis,
> 
> ...
> >>> os.environ['NO_SCIPY_IMPORT']='True'
> >>> from scipy import *
> Skip importing scipy packages (NO_SCIPY_IMPORT=True)
> >>> k
> matrix([[ 400.        ,  400.        ,    0.        ,    0.        ],
>        [   0.        ,    0.        ,  400.        ,  400.        ],
>        [   0.        ,  346.41016151,    0.        ,  173.20508076],
>        [ 346.41016151,    0.        ,  173.20508076,    0.        ]])
> >>> k.I
> Traceback (most recent call last):
>   File "<pyshell#5>", line 1, in ?
>     k.I
>   File "C:\Python\Lib\site-packages\scipy\base\matrix.py", 
> line 204, in getI
>     return matrix(linalg.inv(self))
>   File 
> "C:\Python\Lib\site-packages\scipy\basic\basic_lite.py", line 
> 103, in inverse
>     return solve_linear_equations(a, Numeric.identity(a.shape[0]))
>   File 
> "C:\Python\Lib\site-packages\scipy\basic\basic_lite.py", line 
> 93, in solve_linear_equations
>     raise LinAlgError, 'Singular matrix'
> LinAlgError: Singular matrix
> >>> 
> ...
> 
> Further to Nils & Fernando's comments, for the following 
> singular matrix k, and with 'NO_SCIPY_IMPORT'='True'  
> 
> ...
> >>> k
> matrix([[ 391.69663728,  407.81602433,    0.        ,    0.        ],
>        [   0.        ,    0.        ,  391.69663728,  407.81602433],
>        [   0.        ,  346.1991378 ,    0.        ,  183.56941791],
>        [ 346.1991378 ,    0.        ,  183.56941791,    0.        ]])
> >>> k.I
> matrix([[ -1.64892268e+13,  -8.74328513e+12,   1.94239968e+13,
>           1.86562414e+13],
>        [  1.58374716e+13,   8.39769695e+12,  -1.86562414e+13,
>          -1.79188325e+13],
>        [  3.10975335e+13,   1.64892268e+13,  -3.66323052e+13,
>          -3.51843721e+13],
>        [ -2.98683685e+13,  -1.58374716e+13,   3.51843721e+13,
>           3.37936702e+13]])
> >>> 
> ...
> 
> Both k matrixes fail however in full scipy... and shows the 
> annoying message, "pythonw.exe has encountered a problem and 
> needs to close.  We are sorry for the inconvenience."
> 
> My platform is winXP, py2.3 using the following binaries: 
> scipy_core-0.8.4.win32-py2.3.exe scipy-0.4.3.win32-py2.3.exe
> 
> scipy_core-0.6.1.win32-py2.3.exe
> and
> scipy-0.4.3.win32-py2.3.exe
> 
> Doesn't works fine together...
> 
> PJR
> 
> P.S. How does the 'NO_SCIPY_IMPORT' environment variable work?
> 
> with
> 
> ...
> >>> os.environ['NO_SCIPY_IMPORT']=1
> 
> Traceback (most recent call last):
>   File "<pyshell#1>", line 1, in ?
>     os.environ['NO_SCIPY_IMPORT']=1  # this will not import 
> full scipy but
>   File "C:\Python\Lib\os.py", line 414, in __setitem__
>     putenv(key, item)
> TypeError: putenv() argument 2 must be string, not int
> ...
> 
> "os.environ['NO_SCIPY_IMPORT']='True'" works, as shown at the 
> top, but 
> 
> ... 
> >>> os.environ['NO_SCIPY_IMPORT']='False'
> >>> from scipy import *
> Skip importing scipy packages (NO_SCIPY_IMPORT=False)
> >>> 
> ...
> 
> Doesn't work as I would have expect it...
> 
> 
> > -----Original Message-----
> > From: scipy-user-bounces at scipy.net
> > [mailto:scipy-user-bounces at scipy.net] On Behalf Of Travis Oliphant
> > Sent: 15 December 2005 00:27
> > To: SciPy Users List
> > Subject: Re: [SciPy-user] Bug in inverse matrixcalculation 
> > for "scipy_core-0.8.4.win32-py2.3.exe"
> > 
> > 
> > Randewijk P-J <pjrandew at sun.ac.za> wrote:
> > 
> > > Dear Travis,
> > >  
> > > Thank-you for the "silent" version (0.8.4) of scipy_core.
> > >  
> > > Unfortunately when trying to invert a singular matrix using
> > scipy_core
> > > 0.8.4, python "crashes" instead of issuing the usual 
> error message:
> > 
> > I'm not seeing this. I'm getting the proper error message.
> > Can you show 
> > us the matrix you are using and give more information about 
> > the platform.
> > 
> > Also, try it when the environment variable NO_SCIPY_IMPORT=1
> > 
> > import os
> > os.environ['NO_SCIPY_IMPORT']=1  # this will not import full
> > scipy but 
> > use only scipy_core\
> > import scipy
> > 
> > Full scipy installs its own (hopefully better) matrix
> > inverse.  We need 
> > to figure out which one is giving you trouble.
> > 
> > -Travis
> >  
> > 
> > _______________________________________________
> > SciPy-user mailing list
> > SciPy-user at scipy.net 
> http://www.scipy.net/mailman/listinfo/scipy-user
> > 
> 
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