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MathGroup Archive 2008

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Exact NullSpace computations

  • To: mathgroup at smc.vnet.net
  • Subject: [mg90799] Exact NullSpace computations
  • From: brey_maastricht at hotmail.com
  • Date: Thu, 24 Jul 2008 05:04:35 -0400 (EDT)

Hello,

I need to compute the (exact) NullSpace of an mxn complex exact
rational matrix M where m>>n (looking at 1766x1425 now).
Moreover, M is pretty sparse and I know the dimensions of the
nullspace because I am able to do a fast rank computation on M with
MatrixRank[M, Modulus->largeprime].

When I simply apply the NullSpace[M] function, the computations take
one whole month to finish.
I am sure there should be a faster way but I don't have a clue yet.
Any suggestions ?

Hope you guys can help me !

Best regards,
Brey from The Netherlands


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