Mailman 3 September 2003 - SciPy-User

ImportError: cannot import name real
by Nils Wagner Sept. 26, 2003

Sept. 26, 2003

Dear experts, there seems to be a bug in latest cvs Traceback (most recent call last): File "pseudospectra.py", line 100, in ? io.write_array(file, A, separator=' ', linesep='\n', precision=5, suppress_small=0, keep_open=1) File "/usr/lib/python2.2/site-packages/scipy_base/ppimport.py", line 226, in __getattr__ module = self._ppimport_importer() File "/usr/lib/python2.2/site-packages/scipy_base/ppimport.py", line 204, in _ppimport_importer module = __import__(name,None,None,['*']) File "/usr/lib/python2.2/site-packages/scipy/io/__init__.py", line 11, in ? from array_import import * File "/usr/lib/python2.2/site-packages/scipy/io/array_import.py", line 13, in ? from Numeric import array, take, concatenate, Float, asarray, real, imag ImportError: cannot import name real Any idea ? Nils

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Re: [SciPy-user] Re: [SciPy-dev] Scheduled release
by Pearu Peterson Sept. 26, 2003

Sept. 26, 2003

On Fri, 26 Sep 2003, Pearu Peterson wrote: > > On Thu, 25 Sep 2003, Travis Oliphant wrote: > > > I would like feedback on a change I made recently to CVS. I noticed > > that LAPACK functions were locking up the interpreter when nans (and/or > > infs) where in the array sent to the routine. > > > > Has this behavior been observed before or is it due to use of ATLAS, > > recently compilation flags etc... > > > > I've "solved" the problem by elminating all nans before calling the > > ATLAS routines. > > > > If anyone has other suggestions for this problem, let me know. Ok, now I can generate these "hangs" (that are acctually just some infinite cycles, I'll investigate them later in LAPACK sources). >>> linalg.eigvals([[1,0],[1e308,5]]) array([ 5.+0.j, 1.+0.j]) >>> linalg.eigvals([[1,0],[NaN,5]]) array([ 5.+0.j, 1.+0.j]) >>> linalg.eigvals([[1,0],[Inf,5]]) # now python is taking almost 100% CPU time. Notice that the "hangs" only occur when input array contains Inf or -Inf, there is no problem with NaN. Also, "hangs" occur in lapack functions like eig, eigvals, schur, etc. but inv, det, solve etc never hang. So, here is my suggestion to solve the problem: use inf_to_num instead of nan_to_num only in those lapack functions that *do* hang. In all other functions use asarray as earlier. Pearu

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ImportError: cannot import name real
by Nils Wagner Sept. 26, 2003

Sept. 26, 2003

Dear experts, There seems to be a bug in latest cvs... Traceback (most recent call last): File "pseudospectra.py", line 100, in ? io.write_array(file, A, separator=' ', linesep='\n', precision=5, suppress_small=0, keep_open=1) File "/usr/lib/python2.2/site-packages/scipy_base/ppimport.py", line 226, in __getattr__ module = self._ppimport_importer() File "/usr/lib/python2.2/site-packages/scipy_base/ppimport.py", line 204, in _ppimport_importer module = __import__(name,None,None,['*']) File "/usr/lib/python2.2/site-packages/scipy/io/__init__.py", line 11, in ? from array_import import * File "/usr/lib/python2.2/site-packages/scipy/io/array_import.py", line 13, in ? from Numeric import array, take, concatenate, Float, asarray, real, imag ImportError: cannot import name real Any idea ? Nils

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Newbie issues in moving to SciPy
by Andy Main Sept. 26, 2003

Sept. 26, 2003

Hi, Sorry if I am repeating messages you always get, but hey nevermind! I really don't quite know where to start with Sci Python, I'm used to Matlab, and am really wondering how similar the programming is. I am basically wanting to output graphics using Chaco, should I be learning Python properly, or don't really have to as it is just a syntax difference to what I am used to? Any links to tutorials would be gratefully received. Thanks Andy.

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Scheduled release
by Travis Oliphant Sept. 26, 2003

Sept. 26, 2003

The release of scipy is coming along, but I think we need to postpone the release until Tuesday as I have found some bugs in special that need addressing. Comments? -Travis Oliphant

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Numeric and Numarray
by Karthikesh Raju Sept. 26, 2003

Sept. 26, 2003

Hi All, Can SciPy (latest version - yet to install it) co exist with numarray and numeric. If i install numeric, will i break my existing (and also future installation capabilities) of scipy. With warm regards Karthik ----------------------------------------------------------------------- Karthikesh Raju, email: karthik(a)james.hut.fi Researcher, http://www.cis.hut.fi/karthik Helsinki University of Technology, Tel: +358-9-451 5389 Laboratory of Comp. & Info. Sc., Fax: +358-9-451 3277 Department of Computer Sc., P.O Box 5400, FIN 02015 HUT, Espoo, FINLAND -----------------------------------------------------------------------

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Matrix sign function
by Nils Wagner Sept. 25, 2003

Sept. 25, 2003

Pearu, I have used linalg.signm with a defective matrix. The results do not fulfill the properties of a certain projector. Please find enclosed my test program. Any comments or suggestions for a further improvement of signm ? Nils

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filter design problem
by Kasper Souren Sept. 25, 2003

Sept. 25, 2003

Hi, It's me doing something wrong, or there is a bug in the signal package. My scipy_version is 0.2.0_alpha_196.4128. I'm trying to create a Butterworth bandpass filter, but somehow the resulting filter is always lowpass. I.e. the plot of the freqz is always 1 at the 0 frequency. Here is some code: from scipy.signal import buttord, butter, freqz n,Wn=buttord([0.4, 0.6], [0.2, 0.7], 3, 45) b,a=butter(n,Wn) gplt.plot(abs(freqz(b,a,1000)[1])) bye, Kasper -- We are not the consumers of the media, we are the product. -Kevin Danaher

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Pdf's/ppt files of the Scipy '03 Presentations
by Karthikesh Raju Sept. 25, 2003

Sept. 25, 2003

Hi, Somewhere deep down, there was a discussion about making the presentation files online, so that people who could not attend SciPy 03 could benefit. i am (kind of) checking the page every now and then, there seems to be no link to these presentation. Dear Organizers, is it possible for us to download the same, may be as one big zip file. With warm regards karthik ----------------------------------------------------------------------- Karthikesh Raju, email: karthik(a)james.hut.fi Researcher, http://www.cis.hut.fi/karthik Helsinki University of Technology, Tel: +358-9-451 5389 Laboratory of Comp. & Info. Sc., Fax: +358-9-451 3277 Department of Computer Sc., P.O Box 5400, FIN 02015 HUT, Espoo, FINLAND -----------------------------------------------------------------------

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Problems with linalg.logm
by Nils Wagner Sept. 24, 2003

Sept. 24, 2003

Dear experts, I tried to do something with linalg.logm I have enclosed the program. Result may be inaccurate, approximate err = 1.32516030853e-09 Traceback (most recent call last): File "logm-test.py", line 36, in ? P1 = P1 + (linalg.logm(z1*identity(7)-A)-linalg.logm(z0*identity(7)-A))/(2*pi*sqrt(-1.)) File "/usr/lib/python2.2/site-packages/scipy/linalg/matfuncs.py", line 225, in logm F -= temp.T File "/usr/lib/python2.2/site-packages/Numeric/UserArray.py", line 58, in __isub__ subtract(self.array, other, self.array) TypeError: return array has incorrect type What is the reason for that ? Nils from scipy import * A = zeros((7,7),Float) A[0,0] = -2.0 A[0,1] = 25.0 A[1,1] = -3.0 A[1,2] = 10.0 A[1,3] = 3.0 A[1,4] = 3.0 A[1,5] = 3.0 A[2,2] = 2.0 A[2,3] = 15.0 A[2,4] = 3.0 A[2,5] = 3.0 A[3,4] = 15.0 A[3,5] = 3.0 A[4,4] = 3.0 A[4,5] = 10.0 A[5,5] = -2.0 A[5,6] = 25.0 A[6,6] = -3.0 nm = 4 # # Center of the circle # gamma = 1.5 # # Radius of the circle # rho = 1.6 # P1 = zeros((7,7),Complex) # for i in arange(0,nm-1): z0 = gamma+rho*exp(2.*pi*i*sqrt(-1.)/nm) z1 = gamma+rho*exp(2.*pi*(i+1)*sqrt(-1.)/nm) P1 = P1 + (linalg.logm(z1*identity(7)-A)-linalg.logm(z0*identity(7)-A))/(2*pi*sqrt(-1.)) C=dot(P1,P1)-P1 print trace(C) print P1

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