Page 19 - Basics of MATLAB and Beyond

a=[123;4 56;789]
matlab responds with

a =
1 2 3
4 5 6
7 8 9

3.2 Concatenating Matrices

Matrices can be made up of submatrices: Try this:

>>b=[a 10*a;-a [1 0 0;0 1 0;0 0 1]]
b =
1 2 3 10 20 30
4 5 6 40 50 60
7 8 9 70 80 90
-1 -2 -3 1 0 0
-4 -5 -6 0 1 0
-7 -8 -9 0 0 1
The repmat function can be used to replicate a matrix:

>>a=[12;34]
a =
1 2
3 4
>> repmat(a,2,3)
ans =
1 2 1 2 1 2
3 4 3 4 3 4
1 2 1 2 1 2
3 4 3 4 3 4

3.3 Useful Matrix Generators
matlab provides four easy ways to generate certain simple matrices.
These are
zeros a matrix filled with zeros
ones a matrix filled with ones
rand a matrix with uniformly distributed random elements
randn a matrix with normally distributed random elements
eye identity matrix
To tell matlab how big these matrices should be you give the functions
the number of rows and columns. For example:

c 2000 by CRC Press LLC