Re: Special Matrix

*To*: mathgroup at smc.vnet.net*Subject*: [mg28242] Re: Special Matrix*From*: "Souvik Banerjee" <s-banerjee at nwu.edu>*Date*: Fri, 6 Apr 2001 01:52:51 -0400 (EDT)*Organization*: Northwestern University, Evanston, IL, US*References*: <9ah5nq$ps0@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Not sure if the shortest but it works: CreateMatrix[n_] := Block[{r,c,m}, Needs["LinearAlgebra`MatrixManipulation`"]; r = ZeroMatrix[1, n]; m = Table[1, {n - 2}, {n - 2}]; c = ZeroMatrix[n - 2, 1]; BlockMatrix[{{r}, {c, m, c}, {r}}] ] The bottleneck seems to be the Table[] operations. If there is a built in function to create a matrix with a constant element then it will speed this up. -Souvik Yoram Pollack <syftech at saad.org.il> wrote in message news:9ah5nq$ps0 at smc.vnet.net... > Hello > I am trying to create a "n x n" matrix with "1" in every position exept in > first and last row, and first and last coulumn, where "0" is needed. In > other words: sqare matrix full of "1" sorounded by "0". > What will be the fastest and shortest way to do it? > > Thanks > Yoram > > >