Download Using MATLAB for analysing generalised linear models

CHAPTER 2. STARTING WITH MATLAB
>> A + B’
ans =
1
2
6
4
8
15
>> A - B’
ans =
1
0
-4
-4
-4
3
>> A * B
ans =
21
54
5
27
51
>> inv( A * B )
ans =
-0.1318
0.0698
0.1395 -0.0543
There are other operations in MATLAB apart from the standard operations. Preceding an operation
with a period (.) causes the operation to be applied on an element by element basis. For example,
consider the following commands:
>> C = [0 -3 4; 5 -4 3]
C =
0
-3
4
5
-4
3
>> D = [1 1 9; -3 0 1]
D =
1
1
9
-3
0
1
>> C * D
??? Error using ==> *
Inner matrix dimensions must agree.
>> C .* D
ans =
0
-3
-15
0
36
3
Here’s another example of MATLAB’s element by element procedure:
>> E = [1:4]
E =
1
2
3
4
>> E * E
??? Error using ==> *
Inner matrix dimensions must agree.
>> E ˆ2
??? Error using ==> ˆ
Matrix must be square.
>> E .ˆ 2
ans =
1
4
9
16
%Eˆ2 is the same as E*E