sparse matrix question

*To*: mathgroup at smc.vnet.net*Subject*: [mg56128] sparse matrix question*From*: Ted Sariyski <tsariysk at craft-tech.com>*Date*: Sat, 16 Apr 2005 03:52:10 -0400 (EDT)*References*: <d3lrsq$sef$1@smc.vnet.net> <200504150847.EAA11518@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

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

**Follow-Ups**:**Re: sparse matrix question***From:*DrBob <drbob@bigfoot.com>

**References**:**Re: Wierd problems with Mathematica - inversion of a 12x12 matrix***From:*David Bailey <dave@Remove_Thisdbailey.co.uk>