# Dividing a Matrix with a column vector

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Lorenzo Pinna on 28 Jan 2021
Commented: Lorenzo Pinna on 28 Jan 2021
Hello everyone.
I am having a problem doing a matrix by vector division. The matrices and vectors are here attached.
The operation would be q_i(10000 X 4)= p_i (10000X4)./P(1X4).
The result should be that each element of the coloumn of p_i have to be divided by the element of P of that column. Thus, giving a result different for each column (equal within the columns since the matrix p_i has this peculiarity). Instead, in my case, the outcome is a matrix 100000X4 whose elements are all equal. I am not able at all in managing this problem. If someone can help me to solve this I would be very grateful.
Thanks!
Lorenzo

Jan on 28 Jan 2021
The p_i, you have provided, is not [10000 x 4] but [4 x 10000]. When I load the files and run:
q_i = p_i.' ./ P;
I get a [10000 x 4] matrix with different values as expected.
Therefore it is not clear, how you have created your q_i. The problem must be a a location, you did not mention yet.
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Lorenzo Pinna on 28 Jan 2021
I am sorry to have not specified that this goes in a loop.
Therefore, I am in a loop
for i=1:N N=10000
for t=1:T T=4
and q_i is (TXN), p_i is (TXN) and P is (1XT).
The exact operation is q_i(t,i)=p_i(t,i)./P(t).
Doing this operation the outcome is the matrix q_i attached above.
Effectively, if I do as I described before, the result which I obtain is correct. I would like to obtain the result you get but inside of the loop. with the q_i's numbers equals within the column and different between.
Thanks and sorry for the incovenient