Heigenvalues is broken
Is it a problem of lapack3.0 of of LinearAlgebra.py? ..................... ==> (Eigenvalues should be (0,2))
a=array([[1,0],[0,1]]) b=array([[0,1],[-1,0]]) M=a+b*complex(0,1.0) Heigenvalues(M) array([-2.30277564, 1.30277564]) print M [[ 1.+0.j 0.+1.j] [ 0.-1.j 1.+0.j]]
On Sunday 18 November 2001 09:40 am, Alessandro Mirone wrote:
Is it a problem of lapack3.0 of of LinearAlgebra.py? ..................... ==> (Eigenvalues should be (0,2))
a=array([[1,0],[0,1]]) b=array([[0,1],[-1,0]]) M=a+b*complex(0,1.0) Heigenvalues(M)
I suspect it is your lapack. On an Athlon running Mandrake Linux with the lapack-3.0-9 package, I get.
a=array([[1,0],[0,1]]) b=array([[0,1],[-1,0]]) M=a+b*complex(0,1.0) Heigenvalues(M) array([ 0., 2.])
-Travis
On Sun, 18 Nov 2001, Travis Oliphant wrote:
On Sunday 18 November 2001 09:40 am, Alessandro Mirone wrote:
Is it a problem of lapack3.0 of of LinearAlgebra.py? ..................... ==> (Eigenvalues should be (0,2))
a=array([[1,0],[0,1]]) b=array([[0,1],[-1,0]]) M=a+b*complex(0,1.0) Heigenvalues(M)
I suspect it is your lapack. On an Athlon running Mandrake Linux with the lapack-3.0-9 package, I get.
a=array([[1,0],[0,1]]) b=array([[0,1],[-1,0]]) M=a+b*complex(0,1.0) Heigenvalues(M) array([ 0., 2.])
This is definitely a hardware/compiler dependant feature. I get the "right" answer on Solaris (with the forte compiler) but the same "wrong" answer as Alessandro on MacOS X/gcc. I've tried fiddling with compiler options on my OS X box, to no avail. -Jeff -- Jeffrey S. Whitaker Phone : (303)497-6313 Meteorologist FAX : (303)497-6449 NOAA/OAR/CDC R/CDC1 Email : jsw@cdc.noaa.gov 325 Broadway Web : www.cdc.noaa.gov/~jsw Boulder, CO, USA 80303-3328 Office : Skaggs Research Cntr 1D-124
On November 19, 2001 02:36 pm, Jeff Whitaker wrote:
This is definitely a hardware/compiler dependant feature. I get the "right" answer on Solaris (with the forte compiler) but the same "wrong" answer as Alessandro on MacOS X/gcc. I've tried fiddling with compiler options on my OS X box, to no avail.
But seemingly it is even stranger than this. Here are my results from Debian unstable using Lapack 3.0 on an Athlon system: Python 2.1.1 (#1, Nov 11 2001, 18:19:24) [GCC 2.95.4 20011006 (Debian prerelease)] on linux2 Type "copyright", "credits" or "license" for more information.
from LinearAlgebra import * a=array([[1,0],[0,1]]) b=array([[0,1],[-1,0]]) M=a+b*complex(0,1.0) Heigenvalues(M) array([ 0., 2.])
Scott
On Sun, 18 Nov 2001, Travis Oliphant wrote:
On Sunday 18 November 2001 09:40 am, Alessandro Mirone wrote:
Is it a problem of lapack3.0 of of LinearAlgebra.py? ..................... ==> (Eigenvalues should be (0,2))
a=array([[1,0],[0,1]]) b=array([[0,1],[-1,0]]) M=a+b*complex(0,1.0) Heigenvalues(M)
I suspect it is your lapack. On an Athlon running Mandrake Linux with the lapack-3.0-9 package, I get.
a=array([[1,0],[0,1]]) b=array([[0,1],[-1,0]]) M=a+b*complex(0,1.0) Heigenvalues(M)
array([ 0., 2.])
This is definitely a hardware/compiler dependant feature. I get the "right" answer on Solaris (with the forte compiler) but the same "wrong" answer as Alessandro on MacOS X/gcc. I've tried fiddling with compiler options on my OS X box, to no avail.
-Jeff
-- Jeffrey S. Whitaker Phone : (303)497-6313 Meteorologist FAX : (303)497-6449 NOAA/OAR/CDC R/CDC1 Email : jsw@cdc.noaa.gov 325 Broadway Web : www.cdc.noaa.gov/~jsw Boulder, CO, USA 80303-3328 Office : Skaggs Research Cntr 1D-124
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Alessandro Mirone schrieb:
Is it a problem of lapack3.0 of of LinearAlgebra.py? ..................... ==> (Eigenvalues should be (0,2))
a=array([[1,0],[0,1]]) b=array([[0,1],[-1,0]]) M=a+b*complex(0,1.0) Heigenvalues(M) array([-2.30277564, 1.30277564]) print M [[ 1.+0.j 0.+1.j] [ 0.-1.j 1.+0.j]]
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On an Athlon running SuSE Linux 7.3 with the lapack-3.0-0 package, I get. [-2.30277564 1.30277564] Nils
participants (5)
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Alessandro Mirone -
Jeff Whitaker -
Nils Wagner -
Scott Ransom -
Travis Oliphant