[PYTHON MATRIX-SIG] PyArray_Transpose [multiarraymodule.c] dumps core

[Andy Dustman]

I was testing some of the LinearAlgebra functions and discovered that
eigenvectors and eigenvalues apparently work fine for ordinary arrays, but
for Matrix instances, I get a core dump (SGI IRIX 5.3, R4400). I did some
tracing around and it appears to happen in PyArray_Transpose when it does
a Py_XDECREF. Note: If I try tracing with pdb, it dumps core immediately
before I get any output.  Matrix is a subclass of array, is it not?
Anyway, I don't know enough about how the Python-C interface works to even
begin to debug this, but I suspect a reference count problem. Hopefully
this is of some use to someone. 

% python
Python 1.4 (Oct 28 1996) [C]
Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam
>>> from LinearAlgebra import eigenvalues
>>> from Numeric import array
>>> a=array([[1,2,3],[4,5,6],[7,8,9]])
>>> a.shape
(3, 3)
>>> u=eigenvalues(a)
>>> u
  1.61168440e+01  -1.11684397e+00  -1.26888098e-15
>>> from LinearAlgebra import eigenvectors
>>> u,v=eigenvectors(a)
>>> u,v
(  1.61168440e+01  -1.11684397e+00  -1.26888098e-15,  0.23197069
0.52532209  0.8186735 
 0.78583024  0.08675134 -0.61232756
 0.40824829 -0.81649658  0.40824829)
>>> from Matrix import Matrix
>>> b=matrix([[1,2,3],[4,5,6],[7,8,9]])
Traceback (innermost last):
  File "<stdin>", line 1, in ?
NameError: matrix
>>> b=Matrix([[1,2,3],[4,5,6],[7,8,9]])
>>> b.shape
(3, 3)
>>> u=eigenvalues(b)
Bus error (core dumped)
% dbx /usr/local/bin/python core
dbx version 3.19 Nov  3 1994 19:59:46
Core from signal SIGBUS: Bus error
(dbx) dump
PyArray_Transpose(0x1002cc90, 0x1002a5f8, 0x2, 0x1b)
["./../NumPy/multiarraymodule.c":153, 0x5fc91f98]
(dbx) list
>* 153          Py_XDECREF(ret);
   154          if (permutation != NULL) free(permutation);
   155          PyArray_Free(op, (char *)axes);
   156          return NULL;
   157  }
   158  
   159  extern PyObject *PyArray_Repeat(PyObject *aop, PyObject *op, int
axis) {
   160          int *counts;
   161          int n, n_outer, i, j, k, chunk, total, tmp;
   162          PyArrayObject *ret, *ap;
(dbx) quit


--
Andy Dustman / Computational Center for Molecular Structure and Design / UGA
You can have my PGP public key by sending mail with subject "send file key".
You can have my PGP secret key when you pry it out of my cold, dead neurons.
http://charon.chem.uga.edu/~andy    mailto:andy@CCMSD.chem.uga.edu    <}+++<


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