sum all successive values in matrix row

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I have a vector A which represents 10 machines defect rate. Matrix B shows a process plan in each row in which the elements show process time of one part on corresponding machine for example; row 1 col 4 shows that this part takes 9 minutes to process on machine 4.I want to multiply each row of B with A such that every non zero element of B is multiplies by the sum of corresponding non zero elements of A. for example;
A=[0.1, 0.2, 0.2, 0.4, 0.2, 0.3, 0.1, 0.1, 0.1, 0.2]
B=[0 0 0 9 0 0 10 0 8 8;
8 0 0 0 7 9 0 0 0 10]
C=[0 0 0 (9+9*(0.4+0.1+0.1+0.2)) 0 0 (10+10*(0.1+0.1+0.2) 0 (8+8*(0.1+0.2)) 8+8*0.2;
(8+8*(0.1+0.2+0.3+0.2) 0 0 0 (7+7*(0.2+0.3+0.2) (9+9*(0.3+0.2)) 0 0 0 (10+10*(0.2))]
I tried cumsum and move sum but they are not giving the right answer.
  3 Comments
summyia qamar
summyia qamar on 13 Aug 2018
non zero elements of B are 4th, 7th 9th and 10th so these elements of A are added and multiplied with 4th element of B. then for 7th element; 7 9 and 10th elements of A are added and them multiplied with 7th element of B

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Accepted Answer

Matt J
Matt J on 13 Aug 2018
Edited: Matt J on 13 Aug 2018
map=(B~=0);
C=cumsum(map.*A,2,'reverse').*B+B

More Answers (1)

Geoff Hayes
Geoff Hayes on 13 Aug 2018
summiya - for the seventh element, you seem to have
(10+10*(0.3+0.1+0.2)
Is the 0.3 a mistake and so should be 0.1 instead?
Regardless, if we assume that B has integers only, then we can determine the indices of the non-zero elements of the first row of B with
nonZeroElementsInB = B(1,:) ~= 0;
We can then determine the sum (from A) of these non-zero elements as
sumNonZeroElementsInA = sum(A(nonZeroElementsInB));
So this will be the sum of all the elements of A corresponding to non-zero elements in the first row of B
(0.4+0.1+0.1+0.2)
You will need to adjust this sum for those elements where you don't want to include all of these values.
  1 Comment
summyia qamar
summyia qamar on 13 Aug 2018
yes thank you for correction.I corrected 0.3 error in question

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