Doing calculation across columns
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Hi there. I have a 4 column by 500 row matrix. How would I add a fifth column that calculates 
, where x is the corresponding value in the second column across the same row.
, where x is the corresponding value in the second column across the same row.Thanks!
采纳的回答
madhan ravi
2019-4-22
D=zeros(500,5);
D=matrix;
D(:,5)=exp((-(matrix(:,2)-75)/2).^2)
3 个评论
Jenny Hall
2020-10-22
I am currently trying to do something similar, in order to carry out a calculation of every value in one column. This code I have written is as follows:
x(:,2) = (((6.64e-34)*(9.5e+9))/((9.274e-24)*(x(:,1)/10000)))
However this only seems to calculate a value for the final row in the column, whilst all of the values come out as 0. The column contains 1024 rows.
Any help would be much appreciated!
x(:,2) = (((6.64e-34)*(9.5e+9))./((9.274e-24)*(x(:,1)/10000)))
% ^^ you might want array division here
Jenny Hall
2020-10-22
Thank you! This worked a treat.
更多回答（1 个）
JULIEN BARBAUD
2019-4-22
编辑：JULIEN BARBAUD
2019-4-22
I think that if you call your input matrix A, and the final result B, then this:
f=@(x) exp( (-(x-75)/2).^2 )
B=[A f(A(:,2))];
should do the trick
EDIT: oops, madhan was quicker
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