Matlab - Common operational symb
>> A = [1 2; 3 4; 5 6]
A =
1 2
3 4
5 6
>> B = [11 12; 13 14; 15 16]
B =
11 12
13 14
15 16
>> C = [1 1; 2 2]
C =
1 1
2 2
>> A*C
ans =
5 5
11 11
17 17
>> A .* B
ans =
11 24
39 56
75 96
>> A .^ 2
ans =
1 4
9 16
25 36
>> v = [1;2;3]
v =
1
2
3
>> 1 ./ v
ans =
1.0000
0.5000
0.3333
>> 1 ./ A
ans =
1.0000 0.5000
0.3333 0.2500
0.2000 0.1667
>> log(v)
ans =
0
0.6931
1.0986
>> exp(v)
ans =
2.7183
7.3891
20.0855
>> v + ones(length(v),1)
ans =
2
3
4
>> length(v)
ans =
3
>> v + 1
ans =
2
3
4
>> A
A =
1 2
3 4
5 6
>> A'
ans =
1 3 5
2 4 6
>> a = [1 15 2 0.5]
a =
1.0000 15.0000 2.0000 0.5000
>> val = max(a)
val =
15
>> [val, ind] = max(a)
val =
15
ind =
2
>> a < 3
ans =
1×4 logical array
1 0 1 1
>> find(a < 3)
ans =
1 3 4
>> A
A =
1 2
3 4
5 6
>> A = magic(3)
A =
8 1 6
3 5 7
4 9 2
>> help magic
magic Magic square.
magic(N) is an N-by-N matrix constructed from the integers
1 through N^2 with equal row, column, and diagonal sums.
Produces valid magic squares for all N > 0 except N = 2.
Reference page for magic
>>
>>
>> [r, c] = find(A >= 7)
r =
1
3
2
c =
1
2
3
>> rand(3)
ans =
0.7577 0.6555 0.0318
0.7431 0.1712 0.2769
0.3922 0.7060 0.0462
>> max(rand(3), rand(3))
ans =
0.7952 0.4456 0.7547
0.8235 0.9502 0.3816
0.6948 0.7094 0.7655
>> max(A,[],1)
ans =
8 9 7
>> A
A =
8 1 6
3 5 7
4 9 2
>> max(A,[],2)
ans =
8
7
9
>> max(max(A))
ans =
9
>> A(:)
ans =
8
3
4
1
5
9
6
7
2
>> max(A)
ans =
8 9 7
>> max(A(:))
ans =
9
>> A = magic(9)
A =
47 58 69 80 1 12 23 34 45
57 68 79 9 11 22 33 44 46
67 78 8 10 21 32 43 54 56
77 7 18 20 31 42 53 55 66
6 17 19 30 41 52 63 65 76
16 27 29 40 51 62 64 75 5
26 28 39 50 61 72 74 4 15
36 38 49 60 71 73 3 14 25
37 48 59 70 81 2 13 24 35
>> sum(A,1)
ans =
369 369 369 369 369 369 369 369 369
>> sum(A,2)
ans =
369
369
369
369
369
369
369
369
369
>> eye(9)
ans =
1 0 0 0 0 0 0 0 0
0 1 0 0 0 0 0 0 0
0 0 1 0 0 0 0 0 0
0 0 0 1 0 0 0 0 0
0 0 0 0 1 0 0 0 0
0 0 0 0 0 1 0 0 0
0 0 0 0 0 0 1 0 0
0 0 0 0 0 0 0 1 0
0 0 0 0 0 0 0 0 1
>> A .* eye(9)
ans =
47 0 0 0 0 0 0 0 0
0 68 0 0 0 0 0 0 0
0 0 8 0 0 0 0 0 0
0 0 0 20 0 0 0 0 0
0 0 0 0 41 0 0 0 0
0 0 0 0 0 62 0 0 0
0 0 0 0 0 0 74 0 0
0 0 0 0 0 0 0 14 0
0 0 0 0 0 0 0 0 35
>> sum(sum(A.*eye(9)))
ans =
369
>> A = magic(3)
A =
8 1 6
3 5 7
4 9 2
>> pinv(A)
ans =
0.1472 -0.1444 0.0639
-0.0611 0.0222 0.1056
-0.0194 0.1889 -0.1028
>> temp = pinv(A)
temp =
0.1472 -0.1444 0.0639
-0.0611 0.0222 0.1056
-0.0194 0.1889 -0.1028
>> temp * A
ans =
1.0000 0.0000 -0.0000
-0.0000 1.0000 0.0000
0.0000 -0.0000 1.0000
