[Numpy-discussion] wired error message in scipy.sparse.eigen function: Segmentation fault

Jankins andyjian430074@gmail....
Wed Jan 27 19:45:06 CST 2010


Dear all,

I am using  scipy '0.8.0.dev6120'. And the scipy.sparse.eigen  function 
always produces error message.

_Description:_
    linalg.eigen(A, k=6, M=None, sigma=None, which='LM', v0=None, 
ncv=None, maxiter=None, tol=0, return_eigenvectors=True)_

Error messages:_

When I use this function in the way :
linalg.eigen(A, k=2, return_eigenvectors=False)

it produces error :
*** glibc detected *** python: double free or corruption (!prev)

when I use :
linalg.eigen(A, k=4, return_eigenvectors=False) or linalg.eigen(A, k=8, 
return_eigenvectors=False)

it produces error :
Segmentation fault

_My goal:_
"A" is an _unsymmetrical CSR sparse matrix_. What I am trying to do is :
1. find a node 's' to delete. For edge (u, v) in all the out-edges and 
in-edges of node 's', I set A[u, v] = 0.0.
2. calculate the largest eigenvalue using linalg.eigen(A, 
return_eigenvectors=False)
3. repeat 1-2 steps many times.

I had used eigen_symmetric function to compute symmetric CSR sparse 
matrix and it works very well. But for the 'eigen' function, it is not 
working very well.

Could you please help me about it? If it does not work, I have to 
rewrite my code in MATLAB, which is what I am trying to avoid.

Thanks so much.

Yours sincerely,
Jankins

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