high memory usage by spdet / memory leak?

[Dmitri A. Sergatskov]

I do not understand why spdet() uses as much memory as it does.

By doing

octave:> n=6000; a=speye(n,n)+0.01*sprandn(n,n,0.001);

octave:> whos a

*** local user variables:

  Prot Name        Size                     Bytes  Class
  ==== ====        ====                     =====  =====
   rwd a        6000x6000                  527740  sparse matrix

Total is 41978 elements using 527740 bytes

octave:> spdet(a)

the octave size grows to 476 MB.
The memory stay that high after the execution (it goes slightly above 600MB 
during
calculations).
The size seems to increase as N^2 and execution time as N^4.
The resident memory size seems to increase after successive execution of spdet()
on the same dataset. The loop:
for i = (1:100) ; spdet(a); endfor

was eventually aborted with

error: SparseMatrix::determinant numeric factorization failed
error: evaluating for command near line 17, column 1

At this moment Octave Virt/Res memory usage was 1190MB/704M

Sincerely,

Dmitri.
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