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rrandommatrixsymmetric

How to generate symmetric random matrix?

I want to generate a random matrix which should be symmetric.

I have tried this:

matrix(sample(0:1, 25, TRUE), 5, 5)

but it is not necessarily symmetric.

How can I do that?

Solution

  • Try this from the Matrix package

    library(Matrix)
x<-Matrix(rnorm(9),3)
x
3 x 3 Matrix of class "dgeMatrix"
           [,1]       [,2]       [,3]
[1,] -0.9873338  0.8965887 -0.6041742
[2,] -0.3729662 -0.5882091 -0.2383262
[3,]  2.1263985 -0.3550972  0.1067264

X<-forceSymmetric(x)
X
3 x 3 Matrix of class "dsyMatrix"
           [,1]       [,2]       [,3]
[1,] -0.9873338  0.8965887 -0.6041742
[2,]  0.8965887 -0.5882091 -0.2383262
[3,] -0.6041742 -0.2383262  0.1067264