CODEWITHSUNDEEP
arraysrmatrixdiagonal
Le1887
Le1887

Reputation: 29

How to make an array of diagonal matrices in R?

I know how I can make an array of N numbers of p*p matrices:

m=array(x, c(p,p,N))

which x could be a vector or a scalar. I want to make an array of diagonal matrices. Each matrix should be diagonal. I tried several ways but they don't work. Does anyone know about it?

Upvotes: 3

Views: 497

Answers (2)

Roland
Roland

Reputation: 132676

If you don't mind using a package, you could use abind:

library(abind)
do.call(abind, c(rep(list(diag(3)), 2), along = 3))
#, , 1
#
#     [,1] [,2] [,3]
#[1,]    1    0    0
#[2,]    0    1    0
#[3,]    0    0    1
#
#, , 2
#
#     [,1] [,2] [,3]
#[1,]    1    0    0
#[2,]    0    1    0
#[3,]    0    0    1

Upvotes: 2

Colonel Beauvel
Colonel Beauvel

Reputation: 31161

It's a little bit clumsy but you can do this:

n = 3
num_of_matrix = 2

array(rep(c(diag(n)),num_of_matrix),c(n,n,num_of_matrix))
#, , 1

#     [,1] [,2] [,3]
#[1,]    1    0    0
#[2,]    0    1    0
#[3,]    0    0    1

#, , 2

#     [,1] [,2] [,3]
#[1,]    1    0    0
#[2,]    0    1    0
#[3,]    0    0    1

Upvotes: 4

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