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MathGroup Archive 2001

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Re: Sparse Matrix, Memory Allocation

  • To: mathgroup at
  • Subject: [mg31642] Re: Sparse Matrix, Memory Allocation
  • From: "Robert Nowak" <robert.nowak at>
  • Date: Fri, 23 Nov 2001 05:46:06 -0500 (EST)
  • References: <9t2tnm$6pi$>
  • Sender: owner-wri-mathgroup at

look at the mathematica help for SparseLinearSolve

SparseLinearSolve[smat, vec] solves a sparse linear system;
the matrix smat is represented in the form {{i1,j1}->a1, {i2,j2}->a2,...}
so that the element at position ik,jk has value ak and all unspecified
elements are taken to be zero.

Robert Nowak (robert.nowak at
IMS Nanofabrication GmbH
A-1020 Wien, Schreygasse 3, Austria
Phone: (+43 1)2144894-32, Fax: (+43 1)2144894-99

Inkyu Rhee <Inkyu.Rhee at> wrote in message
news:9t2tnm$6pi$1 at
> I have a 70000 by 70000(or more) banded sparse matrix.
> and this matrix will be updated by specific law for 50 loops.
> In each loop, I need to linear solution of this.
> My prblems are:
> I could not specify this matrix:
> K=Table[0,{70000},{70000}];(* Initialize the matrix K *)
> when I trying this in my machines ((1) sun:ram 750M, swap 2665M,
> (2) window:A800mhz, 128Mb),
> machine gives me 'Out of Memory, Exiting'.
> How do you specify this matrix efficiently?
> If this works well, I will update these components of matrix
> using certain law. Then I need to solve the equations.
> Developer`SparseLinearSolve[K,x]
> I tried this part using 10000 by 10000 instead of 70000.
> It also give me 'Out of Memory ...'.
> Thanks for any help,
> I. Rhee

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