How to do matrix or table multiplication?

3 vues (au cours des 30 derniers jours)
raghavendra kandukuri
raghavendra kandukuri le 6 Sep 2019
Hi,
I have this two tables or matrix, where i am looking to perform the addition of 1st element in the first matrix of first row with the all element in the first row of second matrix and similarly with the second element in the first matrix of first row with the all the elements of first row in second matrix. Similarly with the second and third row elements.
Is there any easy way or formula to do this? even if the size of the matrix changes
Example:
IntakeTable = [0 3 2
4 2 2
4 4 4 ];
ExhaustTable = [0 3 2
4 2 2
2 2 2 ];
resultTable =[0+0 0+3 0+2 3+0 3+3 3+2 2+0 2+3 2+2
4+4 4+2 4+2 2+4 2+2 2+2 2+4 2+2 2+2
4+2 4+2 4+2 4+2 4+2 4+2 4+2 4+2 4+2]

Réponse acceptée

Walter Roberson
Walter Roberson le 6 Sep 2019
resultTable = kron(IntakeTable,ones(1,size(ExhaustTable,2))) + repmat(ExhaustTable,1,size(IntakeTable,2));

Plus de réponses (2)

Bjorn Gustavsson
Bjorn Gustavsson le 6 Sep 2019
Looping seems simplest and most easily readable for humans:
szI = size(IntakeTable);
szE = size(ExhaustTable);
resultTable = zeros(size(ExhaustTable,1),size(ExhaustTable,2)*size(IntakeTable))
for i1 = 1:szI(2),
resultTable(:,(1:szE,2)+(i1-1)*szE(2)) = repmat(IntakeTable(:,i1),1,szE(2)) + ...
ExhaustTable;
end
HTH
  1 commentaire
raghavendra kandukuri
raghavendra kandukuri le 6 Sep 2019
Thank you@ Bjorn Gustavsson

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Adam Danz
Adam Danz le 6 Sep 2019
Modifié(e) : Adam Danz le 6 Sep 2019
resultTable = repmat(ExhaustTable,1,3) + repelem(IntakeTable,1,3)
Or, if the number of columns vary,
resultTable = repmat(ExhaustTable,1,size(IntakeTable,2)) + repelem(IntakeTable,1,size(ExhaustTable,2))

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