Re: sparse matrix question
- To: mathgroup at smc.vnet.net
- Subject: [mg56162] Re: [mg56128] sparse matrix question
- From: DrBob <drbob at bigfoot.com>
- Date: Sun, 17 Apr 2005 03:07:10 -0400 (EDT)
- References: <d3lrsq$sef$1@smc.vnet.net> <200504150847.EAA11518@smc.vnet.net> <200504160752.DAA24641@smc.vnet.net>
- Reply-to: drbob at bigfoot.com
- Sender: owner-wri-mathgroup at wolfram.com
l={{a,b},{c,d},{e,f}};
p={3,4,6};
SparseArray@
Flatten[Transpose[{p,l}]/.{a_Integer,{b_,c_}}\[RuleDelayed]{Rule[{1,a},b],\
Rule[{2,a},c]}]
SparseArray[<\[InvisibleSpace]6\[InvisibleSpace]>,{2,6}]
Normal@%
{{0,0,a,c,0,e},{0,0,b,d,0,f}}
%[[All,3]]
{a,b}
Bobby
On Sat, 16 Apr 2005 03:52:10 -0400 (EDT), Ted Sariyski <tsariysk at craft-tech.com> wrote:
> Hi,
>
> I have a list
> l={{a,b},{c,d},{e,f}}
> and a list of pointers to the non-zero columns of a
> sparse matrix e.g. p={3,4,6}:
> | 0 0 a c 0 d 0 ... |
> m= | |
> | 0 0 b d 0 e 0 ... |
>
> What is the best way to do this? How can I address a column in
> mathematica?
>
> Thanks,
> Ted
>
>
>
>
>
>
>
--
DrBob at bigfoot.com
- References:
- Re: Wierd problems with Mathematica - inversion of a 12x12 matrix
- From: David Bailey <dave@Remove_Thisdbailey.co.uk>
- sparse matrix question
- From: Ted Sariyski <tsariysk@craft-tech.com>
- Re: Wierd problems with Mathematica - inversion of a 12x12 matrix