Re: Sparse Matrix, Memory Allocation

• To: mathgroup at smc.vnet.net
• Subject: [mg31671] Re: Sparse Matrix, Memory Allocation
• From: "Lawrence A. Walker Jr." <lwalker701_remove_ at earthlink.net>
• Date: Fri, 23 Nov 2001 05:47:13 -0500 (EST)
• Organization: Morgan State University, COMSARE
• References: <9t2tnm\$6pi\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Hi Inkyu,

You don't have to initialize the entire matrix when using the
SparseLinearSolve[] function.  I suggest specifying only the bands of
the matrix using the following for K: {{1,1}->a1, {1,2}->a2, ...,
{K,N}->aM}.

K=Table[0,{70000},{70000}];(* Initialize the matrix K *)

Lawrence

Inkyu Rhee wrote:

> 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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