[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 02:45:23 EST 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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