Finding sorted rows in a matrix

outsx = [
     1     1
     2     1
     3     1
     1     2
     2     2
     3     2
     1     3
     2     3
     3     3];
ii = find(outsx(:,2)>=outsx(:,1))
ii = 6×1
     1
     4
     5
     7
     8
     9

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Marco Gaetani d'Aragona 2021-3-20

Hi,

I would need a more general formulation, cosidering matrixes with different number of rows and columns

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Answer 3

Star Strider 2021-3-20

0
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Two approaches:

 for k = 1:size(outsx,1)
     TF(k,:) = issorted(outsx(k,:),2,'ascend')
 end
 Result = find(TF)
 
 TF = outsx(:,2) >= outsx(:,1);
 Result = find(TF)

both producing:

.

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Marco Gaetani d'Aragona 2021-3-20

Hi,

I need to perform this check for matrixes nxm, so I need a faster procedure without employing for cycles.

the cyclist 2021-3-20

FYI, just because code has a for loop does not necessarily mean it is slower than other solutions.

Finding a solution that works is the first step (partly to verify that the solution does what you want), and then thinking about readability and optimization follows.

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