Re: Creating a symmetric matrix
- To: mathgroup at smc.vnet.net
- Subject: [mg46855] Re: Creating a symmetric matrix
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Fri, 12 Mar 2004 02:02:40 -0500 (EST)
- Organization: Universitaet Leipzig
- References: <c2p9ld$dns$1@smc.vnet.net>
- Reply-to: kuska at informatik.uni-leipzig.de
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
ll = PadRight[#, 4, 0] & /@ Table[a[j, i], {j, 1, 4}, {i, 1, j}];
ll = ll + MapIndexed[If[Equal @@ #2, 0, #1] & , Transpose[ll], {2}]
??
Regards
Jens
Mark Coleman wrote:
>
> Greetings,
>
> How can I efficiently build a symmetric matrix from an upper triangular
> one, i.e., extract the upper triangular elements and insert them into
> the lower triangle in such a way as to make the resulting square matrix
> symmetric?
>
> Thanks,
>
> Mark