MathGroup Archive 2005

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: sparse matrix question


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


  • Prev by Date: Re: sparse matrix question
  • Next by Date: How can I get a nonscalar logical variable into a compiled function?
  • Previous by thread: sparse matrix question
  • Next by thread: Re: sparse matrix question