Mailman 3 May 2011 - NumPy-Discussion

f2py and lapack DLARUV
by Stephane Raynaud May 19, 2011

May 19, 2011

Hi, trying to build a fortran extension linked to lapack (f77), I faced a problem that I reduced to the following example. ------------ testfile.f90 ------------ subroutine testfunc integer,parameter :: n=2 integer :: iseed(4) real(kind=8) :: x(n) iseed = (/0,1,3,4/) call DLARUV(iseed, n, x) end subroutine testfunc -------------------------------------- Then : f2py -c -m testmod -llapack -lblas -L/home/raynaud/soft/lapack_gfortran/lib testfile.f90 It rises the following error (using gfortran) : /usr/bin/ld: /home/raynaud/soft/lapack_gfortran/lib/liblapack.a(dlaruv.o): relocation R_X86_64_32S against `.data' can not be used when making a shared object; recompile with -fPIC /home/raynaud/soft/lapack_gfortran/lib/liblapack.a: could not read symbols: Bad value BLAS and LAPACK where compilated with gfortran and options '-fPIC -O3'. I tried to use the DATA statement directly in a subroutine that I converted to a python module, and it worked. Any idea ? Thanks. -- Stephane Raynaud

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Importing a list into a structured numpy array, what is my error?
by Robert Love May 19, 2011

May 19, 2011

my_list = [[1960, 'W0'],[2001, 'D5']] my_arr = np.array(my_list, dtype=('uint', '|S2')) gives me an error I don't understand: ValueError: mismatch in size of old and new data-descriptor What are the old and new? I get the same problem if try np.asarray() If I make the dtype ('|S4', '|S4') I can read in as strings without errors How do I convert a list of mixed types to a structured array? Thanks for any pointers.

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[ANN] Courses in Colorado: "Introduction to Python and Python for Scientists and Engineers" - one day left for early bird rate
by Mike Müller May 18, 2011

May 18, 2011

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Windows dev-build Numpy 1.6.1
by Wieland Brendel May 18, 2011

May 18, 2011

Hello, I am glad Mark was able to resolve the bug in einsum very fast since I am heavily relying on this function. I am working on a Windows 7 64 bit system with latest Python 2.6. I tried to build numpy from SVN following along http://www.scipy.org/Build_for_Windows After installing numpy I received the error RuntimeError: module compiled against ABI version 1000009 but this version of numpy is 2000000 This seems to be related to my Scipy installation, so I tried to build Scipy as well but couldn't get around installing ATLAS (I am used to using the superpacks...). Could somebody help me out? Maybe even with a 1.6.1 branch dev build? Thanks very much in advance!! Wieland

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Re: [Numpy-discussion] strange dimension-dependent behaviour of einsum
by Wieland Brendel May 18, 2011

May 18, 2011

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cPickle.load says 'invalid signature'
by Neal Becker May 18, 2011

May 18, 2011

The file is pickle saved on i386 and loaded on x86_64. It contains a numpy array (amoungst other things). On load it says: RuntimeError: invalid signature Is binary format not portable?

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strange dimension-dependent behaviour of einsum
by Wieland Brendel May 18, 2011

May 18, 2011

Hello, I am encountering a very strange behaviour of einsum on my machine. I tracked the problem down to the following test code: from numpy import * T = random.random((3,10,10)) W = random.random((3,10,7,275)) print all(einsum('ij...,j...->i...',T[0],W[0]) + einsum('ij...,j...->i...',T[1],W[1]) + einsum('ij...,j...->i...',T[2],W[2]) - einsum('pij,pjts->its',T,W)< 1e-10) print sum(abs(einsum('ij...,j...->i...',T[0],W[0]) + einsum('ij...,j...->i...',T[1],W[1]) + einsum('ij...,j...->i...',T[2],W[2]) - einsum('pij,pjts->its',T,W))) On my machine the equality is not fulfilled. However, this depends, strange enough, on the dimensions of W: if the last dimension e.g. is 500 instead of 275, things work again and the equality is fulfilled. Are you encountering similar problems or is this just my machine/installation? Since I am heavily relying on einsum but can't trust my code any more, I am happily waiting for you answers. Thanks a lot! Wieland

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Linear assignment problem: Jonker-Volgenant algorithm
by Gael Varoquaux May 17, 2011

May 17, 2011

Following a suggestion by Joseph, I am trying to implement the Jonker-Volgenant algorithm for best linear assignment in Python, using numpy. Unsuprisingly, it is proving time-costly. I cannot afford to spend too much time on this, as it not to solve a problem of mine, but for the scikits.learn. Thus I was wondering if someone had a BSD-licensed Python version of the algorithm that he would be willing to share. Cheers, Gael

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fitting legendre polynomial
by Wolfgang Kerzendorf May 17, 2011

May 17, 2011

Hello, The science package I'm using fits legendre polynomials to data. I heard it is more stable than the normal polynomials for a fit. Is there a polyfit for legendre polynomials? How do I do that with the new legendre polynomials module? Thanks Wolfgang

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Trying to turn warning to errors
by Ondrej Marsalek May 17, 2011

May 17, 2011

Dear all, I am trying to turn Python warnings to errors, but it does not work as expected with numpy. The following two piece of code work: $ python -W error -c 'import warnings; import numpy; warnings.warn("test", numpy.core.numeric.ComplexWarning)' Traceback (most recent call last): File "<string>", line 1, in <module> numpy.core.numeric.ComplexWarning: test $ python -W error -c 'import warnings; import numpy; raise numpy.core.numeric.ComplexWarning' Traceback (most recent call last): File "<string>", line 1, in <module> numpy.core.numeric.ComplexWarning while this does not (i.e. still produces just a warning): $ python -W error -c 'import numpy; x=numpy.ones(2); x+=1j' numpy.core.numeric.ComplexWarning: Casting complex values to real discards the imaginary part This is with Python 2.6.6 and numpy 1.5.1, but also confirmed with Python 2.7. Thanks for any suggested solutions, Ondrej Marsalek

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