Maxk gives an incorrect result

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Kk
Kk 2022-4-22
评论： Voss 2022-4-23
Hi all,
I am trying to get 4 different value from a matrix. I am using maxk to find these values indices. Maxk can find first two maximum value with indices but when I try to find third it gives an incorrect result. for example when ı select row "1" it found 2 maximum value with their column in matrix and gives me 7-15 then I select 7 for my row it should needs to give me 8th column but it gives 1. I cannot understand why
Here is my code:
for i = nodes
if i == 1 [~,seed] = maxk(m(1:n),2);
end
end
s1 = seed(1,1);
s2 = seed(1,2);
for i = nodes
if i == 7 [~,seed2] = maxk(m(7,n),1);
end
end

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Voss
Voss 2022-4-22
Ran in:
For the case that i == 1 you have:
maxk(m(1:n),2)
m(1:n)is the first n elements of m (going in column-major order, which is what MATLAB uses). For example:
m = magic(4)
m = 4×4
16 2 3 13 5 11 10 8 9 7 6 12 4 14 15 1
n = 6;
m(1:n)
ans = 1×6
16 5 9 4 2 11
For the case that i == 7, you have:
maxk(m(7,n),2)
m(7,n) is the element(s) of m at row 7, column(s) n. If n is a scalar, that's one element. For example:
m = magic(7)
m = 7×7
30 39 48 1 10 19 28 38 47 7 9 18 27 29 46 6 8 17 26 35 37 5 14 16 25 34 36 45 13 15 24 33 42 44 4 21 23 32 41 43 3 12 22 31 40 49 2 11 20
n = 6;
m(7,n)
ans = 11
If you want to use maxk on rows of m, then the syntax would be:
maxk(m(1,:),2) % using first row of m
maxk(m(7,:),2) % using 7th row of m
For example (using m as the 7x7 magic square still):
m(1,:)
ans = 1×7
30 39 48 1 10 19 28
m(7,:)
ans = 1×7
22 31 40 49 2 11 20
[~,seed] = maxk(m(1,:),2)
seed = 1×2
3 2
[~,seed2] = maxk(m(7,:),2)
seed2 = 1×2
4 3
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Kk
Kk 2022-4-23
That is exactly the same thing what I was trying to say and do. Thank you very much mate.

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