1. Tutorial Matlab - USP

Manipulação de matrizes:
>> A = [1 2 3;4 5 6;7 8
9]
A =
1 2 3
4 5 6
7 8 9
>> A(3,3)=A(1,3)+A(3,1)
A =
1 2 3
4 5 6
7 8 10
Matriz vazia: x = [ ]
>> b = A(:)
b =
1
4
7
2
5
8
3
6
10
Exemplo de remoção de linhas e colunas de uma matriz:
>> A(:) = 1:9
A =
1 4 7
2 5 8
3 6 9
Exemplos:
>> diag(1:4)
ans =
1 0 0 0
0 2 0 0
0 0 3 0
0 0 0 4
>> diag(1:4,1)
ans =
0 1 0 0 0
0 0 2 0 0
0 0 0 3 0
0 0 0 0 4
0 0 0 0 0
>> diag([1 -1 -8])
ans =
1 0 0
0 -1 0
0 0 -8
>> A = [1 2 3;4 5 6;7 8 9]
A =
1 2 3
4 5 6
7 8 9
>> rand(4,3)
ans =
0.2190 0.9347 0.0346
0.0470 0.3835 0.0535
0.6789 0.5194 0.5297
0.6793 0.8310 0.6711
>> A(:,[2 3])=[]
A =
1
2
3
>> diag(A)
ans =
1
5
9
>> diag(A,-1)
ans =
4
8
>> diag(A,2)
ans =
3
>> zeros(2,3)
ans =
0 0 0
0 0 0
>> zeros(2)
ans =
0 0
0 0
>> rand(4,3)
ans =
0.0077 0.6868 0.5269
0.3834 0.5890 0.0920
0.0668 0.9304 0.6539
0.4175 0.8462 0.4160
>> A(:) = 1:9
A =
1 4 7
2 5 8
3 6 9
>> A(:,[2,3]) = zeros(3,2)
A =
1 0 0
4 0 0
7 0 0
>> 3*ones(3)
ans =
3 3 3
3 3 3
3 3 3
>> eye(2,3)
ans =
1 0 0
>> eye(3)
ans =
0 1 0
1 0 0
0 1 0
0 0 1
>> -1*eye(3)
ans =
-1 0 0
0 -1 0
0 0 -1
>> ones(3)
ans =
1 1 1
1 1 1
1 1 1
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