Re: How to construct symmetric matrix from just a one half matrix
- To: mathgroup at smc.vnet.net
- Subject: [mg110371] Re: How to construct symmetric matrix from just a one half matrix
- From: Julian <julianhaw at gmail.com>
- Date: Wed, 16 Jun 2010 05:35:39 -0400 (EDT)
- References: <hv76li$k4j$1@smc.vnet.net>
On Jun 15, 2:30 am, dragec <culino... at gmail.com> wrote: > please help me with simple to apply function that will construct > symmetric matrix from given just a half matrix with diagonal. > Eg: > > From: > 1 0 0 0 > 2 3 0 0 > 4 9 5 0 > 2 2 3 4 > > To give: > > 1 2 4 2 > 2 3 9 2 > 4 9 5 3 > 2 2 3 4 Let's say the matrix with the zeros is called A. A possibly clunky way to achieve your goal is to do f[A_?MatrixQ]:= A + Transpose[A] - DiagonalMatrix[Diagonal[A]]