Max value of row in matrix and creating new matrix

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Etan Cole
Etan Cole le 7 Oct 2014
Commenté : Star Strider le 8 Oct 2014
I want something like this matrixa=[12 33 44;26 59 14;15 99 54] matrixb=[26 89 95;23 54 12;2 54 43]
and to get output like this
matrixc=[15 99 54;26 89 95]
calculate the sum of rows in both matrix and to create a new matrix with the two rows that have the greatest sum value like example above. can it be done with max function ? thanks in advance :)
  2 commentaires
José-Luis
José-Luis le 7 Oct 2014
What have you tried so far?
Etan Cole
Etan Cole le 7 Oct 2014
clear; a=[15 9 7;8 5 5;1 7 4]; b=[6 5 9;8 2 5;5 4 4]; [C,I]=max(sum(a,1)); [C1,I1]=max(sum(b,1)); matrix=[a(I,:);b(I1,:)];

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Réponses (2)

Star Strider
Star Strider le 7 Oct 2014
This works:
sa = sum(matrixa,2);
sb = sum(matrixb,2);
c = zeros(size(matrixa));
q1 = matrixa(sa > sb,:);
q2 = matrixb(sb > sa,:);
c(sa > sb,:) = matrixa(sa > sb,:);
c(sb > sa,:) = matrixb(sb > sa,:);
  3 commentaires
Star Strider
Star Strider le 7 Oct 2014
Misread it at first. This works:
sa = sum(matrixa,2);
sb = sum(matrixb,2);
mab = [matrixa; matrixb];
sab = [sa; sb];
[srtab,ix] = sort(sab,'descend');
matrixc = mab(ix(1:2),:);
Star Strider
Star Strider le 8 Oct 2014
With respect to your solution, what happens if the two largest row sums happen to be in the same matrix?
My code accounts for that, so that ‘c’ contains the rows of either matrix with the largest row sums.
Your code selects the largest row sums from ‘matrixa’ and ‘matrixb’. They may not be the largest row sums of the two matrices.

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Etan Cole
Etan Cole le 7 Oct 2014
i got it working like this. thanks for the help
[C,I]=max(sum(a,2)); [C1,I1]=max(sum(b,2)); rezultat=[a(I,:);b(I1,:)];

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