Re: How to construct symmetric matrix from just a one half matrix

*To*: mathgroup at smc.vnet.net*Subject*: [mg110393] Re: How to construct symmetric matrix from just a one half matrix*From*: "Sjoerd C. de Vries" <sjoerd.c.devries at gmail.com>*Date*: Wed, 16 Jun 2010 05:39:48 -0400 (EDT)*References*: <hv76li$k4j$1@smc.vnet.net>

fun[m_?MatrixQ]:= m + Transpose[m] - m IdentityMatrix[Length[m]] or fun[m_?MatrixQ]:= m + Transpose[m] - UpperTriangularize[m] or fun[m_?MatrixQ]:= m + Transpose[m] - DiagonalMatrix[Tr[m, List]] Cheers -- Sjoerd On Jun 15, 8:30 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