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Not enough memory to perform factorization expm scipy.sparse.linalg.splu

I have been trying to use TieDIE. In a few words, this software includes an algorithm that find significant subnetwork when you pass some query nodes and a network. With smaller networks It works just fine, but the network that I am interested in, is quite big, It has 21988 nodes and 360474 edges. TieDIE generates an initial network kernel using scipy (although Matlab is also an option to generate this kernel I do not own a license). During the generation of this kernel I get the following error:

Not enough memory to perform factorization. Traceback (most recent call last):   
File "Trials.py", 
line 44, in <module> diffuser = SciPYKernel(network_path)   
File "lib/kernel_scipy.py", 
line 83, in __init__ self.kernel = expm(time_T*L)   
File "/home/agmoreno/TieDIE-trials/TieDIE/local/lib/python2.7/site-packages/scipy/sparse/linalg/matfuncs.py",
line 602, in expm return _expm(A, use_exact_onenorm='auto')   
File "/home/agmoreno/TieDIE-trials/TieDIE/local/lib/python2.7/site-packages/scipy/sparse/linalg/matfuncs.py",
line 665, in _expm X = _solve_P_Q(U, V, structure=structure)   
File "/home/agmoreno/TieDIE-trials/TieDIE/local/lib/python2.7/site-packages/scipy/sparse/linalg/matfuncs.py",
line 699, in _solve_P_Q return spsolve(Q, P)   
File "/home/agmoreno/TieDIE-trials/TieDIE/local/lib/python2.7/site-packages/scipy/sparse/linalg/dsolve/linsolve.py",
line 198, in spsolve Afactsolve = factorized(A)   
File "/home/agmoreno/TieDIE-trials/TieDIE/local/lib/python2.7/site-packages/scipy/sparse/linalg/dsolve/linsolve.py",
line 440, in factorized return splu(A).solve   
File "/home/agmoreno/TieDIE-trials/TieDIE/local/lib/python2.7/site-packages/scipy/sparse/linalg/dsolve/linsolve.py", 
line 309, in splu ilu=False, options=_options) 
MemoryError

What is the most interesting thing about this is that I am using a cluster computer that has 64 cpus, and 700GB or RAM and the software peaks at 1.3% of Memory usage (~10GB), according to a ps monitoring, at some moment of execution and crushing later. I have been told that there is no limit in the usage of RAM... So I really have no clue about what could be happening ...

Maybe someone here could help me on finding an alternative to scipy or solving it.

Is it possible that the memory error comes because of just one node is being used? In this the case, how could I distribute the work across the nodes?

Thanks in advance.

Solution

  • That's right, for a very large network like that you'll need high memory on a single node. The easiest solution is of course a workaround, either:

    (1) Is there any way you reduce the size of your input network while still capturing relevant biology? Maybe just look for all the nodes 2 steps away from your input nodes?

    (2) Use the new Cytoscape API to do the diffusion for you: http://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1005598 (https://github.com/idekerlab/heat-diffusion)

    (3) Use PageRank instead of computing a heat kernel (not ideal, as we've shown that Diffusion tends to work better on biological networks).

    Hope this helps! -Evan Paull (TieDIE developer/lead author)