[SciPy-dev] lapack and blas
eric
eric at scipy.org
Sat Jan 19 13:57:15 CST 2002
Hey Pearu,
> However, a bad news is that lapack and atlas lapack functions are not
> compatible.
> For example,
> >>> LU,ipiv,X,info=flapack.c_sgesv([[1,2],[3,4]],[1,1])
> >>> print X
> [-0.5 0.5]
For some reason, this is solving using the transpose of the matrix.
1 3 x1 = 1 --> x1 = -0.5
2 4 x2 1 x2 = 0.5
Is this a problem with c_sgesv, or is f2py doing something incorrectly with the matrix transpose stuff? I need to look at the magic your doing under the covers to handle all this, since I haven't figured out how you'd do it completely transparently in a way that never leads to ambiguity and also maintains efficiency.
Still, this is wrapping the C version of the function, so it should be the "trivial" case since nothing special needs to be done to the matrix.
> >>> LU,ipiv,X,info=flapack.f_sgesv([[1,2],[3,4]],[1,1])
> >>> print X
> [-0.99999994 0.99999994]
As you know, this is the correct answer.
eric
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