How to combine two matrices to create a block-diagonal matrix in R?
A block-diagonal matrix means that a matrix added to another matrix at the end the last element. For example, if we have a matrix with nine values and the other matrix also has nine values then the second matrix will be added to the first matrix and the elements below first matrix will be zero and the elements above the second matrix will also be zero.
Example
Live Demo
M1<-matrix(1:9,ncol=3)
M1
Output
[,1] [,2] [,3]
[1,] 1 4 7
[2,] 2 5 8
[3,] 3 6 9
Example
Live Demo
M2<-matrix(10:18,ncol=3)
M2
Output
[,1] [,2] [,3]
[1,] 10 13 16
[2,] 11 14 17
[3,] 12 15 18
Example
rbind(cbind(M1,matrix(0,nrow=nrow(M1),ncol=ncol(M2))),cbind(matrix(0,nrow=nrow(M2),ncol=ncol(M1)),M2))
Output
[,1] [,2] [,3] [,4] [,5] [,6]
[1,] 1 4 7 0 0 0
[2,] 2 5 8 0 0 0
[3,] 3 6 9 0 0 0
[4,] 0 0 0 10 13 16
[5,] 0 0 0 11 14 17
[6,] 0 0 0 12 15 18
Example
Live Demo
M3<-matrix(1:25,nrow=5)
M3
Output
[,1] [,2] [,3] [,4] [,5]
[1,] 1 6 11 16 21
[2,] 2 7 12 17 22
[3,] 3 8 13 18 23
[4,] 4 9 14 19 24
[5,] 5 10 15 20 25
Example
Live Demo
M4<-matrix(26:50,ncol=5)
M4
Output
[,1] [,2] [,3] [,4] [,5]
[1,] 26 31 36 41 46
[2,] 27 32 37 42 47
[3,] 28 33 38 43 48
[4,] 29 34 39 44 49
[5,] 30 35 40 45 50
Example
rbind(cbind(M3,matrix(0,nrow=nrow(M4),ncol=ncol(M4))),cbind(matrix(0,nrow=nrow(M4),ncol=ncol(M3)),M4))
Output
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,] 1 6 11 16 21 0 0 0 0 0
[2,] 2 7 12 17 22 0 0 0 0 0
[3,] 3 8 13 18 23 0 0 0 0 0
[4,] 4 9 14 19 24 0 0 0 0 0
[5,] 5 10 15 20 25 0 0 0 0 0
[6,] 0 0 0 0 0 26 31 36 41 46
[7,] 0 0 0 0 0 27 32 37 42 47
[8,] 0 0 0 0 0 28 33 38 43 48
[9,] 0 0 0 0 0 29 34 39 44 49
[10,] 0 0 0 0 0 30 35 40 45 50
Example
Live Demo
M5<-matrix(sample(1:5,25,replace=TRUE),nrow=5)M5
Output
[,1] [,2] [,3] [,4] [,5]
[1,] 2 2 3 1 2
[2,] 2 4 1 5 4
[3,] 4 1 5 4 2
[4,] 2 4 4 2 5
[5,] 5 1 2 5 3
Example
Live Demo
M6<-matrix(sample(6:10,25,replace=TRUE),ncol=5)
M6
Output
[,1] [,2] [,3] [,4] [,5]
[1,] 10 9 9 6 6
[2,] 8 7 10 9 8
[3,] 8 9 9 8 9
[4,] 7 8 6 8 7
[5,] 8 9 6 8 7
Example
rbind(cbind(M5,matrix(0,nrow=nrow(M6),ncol=ncol(M6))),cbind(matrix(0,nrow=nrow(M6),ncol=ncol(M5)),M6))
Output
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,] 3 1 3 1 3 0 0 0 0 0
[2,] 4 2 3 1 5 0 0 0 0 0
[3,] 5 4 3 5 4 0 0 0 0 0
[4,] 1 3 5 1 5 0 0 0 0 0
[5,] 1 2 2 4 5 0 0 0 0 0
[6,] 0 0 0 0 0 8 8 7 6 10
[7,] 0 0 0 0 0 6 6 8 10 7
[8,] 0 0 0 0 0 9 6 7 10 9
[9,] 0 0 0 0 0 10 6 10 6 7
[10,] 0 0 0 0 0 10 10 9 7 6
Example
Live Demo
M7<-matrix(round(rnorm(36),0),nrow=6)
M7
Output
[,1] [,2] [,3] [,4] [,5] [,6]
[1,] 1 0 2 -1 1 0
[2,] -2 0 2 0 0 -1
[3,] -1 0 0 0 0 0
[4,] 0 0 1 1 1 0
[5,] 1 -1 0 -1 2 1
[6,] 0 1 0 0 2 -1
Example
Live Demo
M8<-matrix(round(runif(36,2,5),0),nrow=6)
M8
Output
[,1] [,2] [,3] [,4] [,5] [,6]
[1,] 3 4 3 3 3 4
[2,] 2 2 2 3 4 5
[3,] 3 2 3 4 4 3
[4,] 3 3 5 2 3 2
[5,] 3 5 4 4 5 2
[6,] 4 2 2 4 2 3
Example
rbind(cbind(M7,matrix(0,nrow=nrow(M8),ncol=ncol(M8))),cbind(matrix(0,nrow=nrow(M8),ncol=ncol(M7)),M8))
Output
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
[1,] 0 0 0 1 -1 1 0 0 0 0 0 0
[2,] -1 1 2 1 -1 1 0 0 0 0 0 0
[3,] 0 0 1 0 1 1 0 0 0 0 0 0
[4,] -1 0 -2 0 1 -3 0 0 0 0 0 0
[5,] 0 1 1 0 1 0 0 0 0 0 0 0
[6,] 0 0 0 0 0 1 0 0 0 0 0 0
[7,] 0 0 0 0 0 0 2 4 2 2 3 4
[8,] 0 0 0 0 0 0 4 4 5 3 3 4
[9,] 0 0 0 0 0 0 3 5 3 4 5 3
[10,] 0 0 0 0 0 0 3 4 5 4 2 5
[11,] 0 0 0 0 0 0 4 3 3 3 4 2
[12,] 0 0 0 0 0 0 5 3 5 2 3 5
Published on 10-Oct-2020 12:07:56
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