[SciPy-dev] Extensions linking to libraries used by numpy/scipy

Tom Loredo loredo at astro.cornell.edu
Tue Mar 7 11:53:03 CST 2006


Robert Kern wrote:

> I'm using OS X 10.4, although I think I build with ATLAS. I think you
> should at least have flapack. Can you successfully call any of the functions
> from scipy.linalg? What versions of numpy/scipy are you using? Can you try "from
> scipy.linalg import flapack"? What does
> 
> In [3]: from numpy import linalg as n_linalg
> 
> In [4]: from scipy import linalg as s_linalg
> 
> In [5]: n_linalg is s_linalg
> Out[5]: False
> 
> give you?

The following is with OS 10.3.9, MacPython 2.4.1, Numpy 0.9.5,
and Scipy 0.4.6:

In [1]: from numpy import linalg as n_linalg

In [2]: from scipy import linalg as s_linalg

In [3]: n_linalg is s_linalg
Out[3]: True

In [4]: from scipy.linalg import flapack

In [5]: scipy.linalg.flapack.dgetrf._cpointer
Out[6]: <PyCObject object at 0x105c1a0>                                         


Huh?  So I tried:

In [10]: from scipy import linalg

In [11]: linalg.flapack.dgetrf._cpointer
Out[11]: <PyCObject object at 0x105c1a0>

So I quit IPython, started it afresh, and:

In [1]: from scipy import linalg

In [2]: linalg.flapack.dgetrf._cpointer
AttributeError: 'module' object has no attribute 'flapack'

In [3]: from scipy.linalg import flapack

In [4]: linalg.flapack.dgetrf._cpointer
AttributeError: 'module' object has no attribute 'flapack'

In [5]: flapack.dgetrf._cpointer
Out[5]: <PyCObject object at 0xd2c0>

In [9]: dir(linalg)
Out[9]: 
['Heigenvalues',
 'Heigenvectors',
 'LinAlgError',
 'ScipyTest',
 '__builtins__',
 '__doc__',
 '__file__',
 '__name__',
 '__path__',
 'cholesky',
 'cholesky_decomposition',
 'det',
 'determinant',
 'eig',
 'eigenvalues',
 'eigenvectors',
 'eigh',
 'eigvals',
 'eigvalsh',
 'generalized_inverse',
 'inv',
 'inverse',
 'lapack_lite',
 'linalg',
 'linear_least_squares',
 'lstsq',
 'pinv',                             
 'singular_value_decomposition',
 'solve',
 'solve_linear_equations',
 'svd',
 'test']       

No "flapack" there---should there be?  Is some import magic
happening that I don't understand?  Is the presence of
"lapack_lite" a hint of something amiss?

-Tom


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