MTL

Hello,

I've been using the Matrix Template Library for a pattern recognition
program.  I basically use the template library for matrix inversion, using
the LU inverse algorithm.  I sometimes get an error when using this, and
I'm not entirely sure why it works sometimes but not all the time.  I get
a seg fault when I apply an LU inverse to a dense 2D matrix (of type
double). The problem seems to stem from deallocation of a vector.  The
following trace was from gdb.

-------------------------------------------------------------------------

Program received signal SIGSEGV, Segmentation fault.
0x4207ac9e in chunk_free () from /lib/i686/libc.so.6
(gdb) up
#1  0x4207ac24 in free () from /lib/i686/libc.so.6
(gdb) up
#2  0x0804ce05 in __malloc_alloc_template<0>::deallocate ()
(gdb) up
#3  0x0804cbfb in __default_alloc_template<true, 0>::deallocate ()
(gdb) up
#4  0x0806206c in simple_alloc<double, __default_alloc_template<true, 0>
>::deal
(gdb) up
#5  0x0805fd45 in _Vector_alloc_base<double, allocator<double>,
true>::_M_deallo
(gdb) up
#6  0x0805ca1d in _Vector_base<double, allocator<double> >::~_Vector_base
()
(gdb) up
#7  0x0805fdb9 in vector<double, allocator<double> >::~vector ()
(gdb) up
#8  0x0805cab5 in mtl::refcnt_ptr<vector<double, allocator<double> >
>::dec ()
(gdb) up
#9  0x0805abb5 in mtl::refcnt_ptr<vector<double, allocator<double> >
>::~refcnt_
(gdb) up
#10 0x08059353 in mtl::dense1D<double, 0>::~dense1D ()
(gdb) up
#11 0x080584e2 in void mtl
lu_inverse<mtl::row_matrix<mtl::gen_dense2D<double, m
ix<mtl::gen_dense2D<double, mtl::gen_rect_offset<0, 0>, 0, 0>,
mtl::gen_rect_ind
(gdb) up
#12 0x08056531 in Path_Class::calc_weights ()
(gdb) up
#13 0x0806586b in Path_Classifier::calc_common_covariance ()
(gdb) up
#14 0x0804dde8 in main ()
(gdb) up
#15 0x42017499 in __libc_start_main () from /lib/i686/libc.so.6

-----------------------------------------------------------------------

Is this a common problem? I'm using g++ 2.96 on a Redhat 7.3 box.  Any
help would be muchly appreciated!!

Thanks,

-Pauline

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