MATLAB: Averaging over certain elements in an array

arraysaverageinterectuniquevector

Hi, I have the following array :

a=[1,1,1;1,2,1;1,3,1;1,7,1;1,8,1;2,4,2;4,5,2;4,6,2;3,3,3;4,5,3;5,6,4;];
rn = unique(a(:,3));

I would like to average all the a(:,1) & a(:,2) such that a(:,3) belongs to elements of rn, and store it another array, say C. For example, in this case, I would like to average C(1,1)=mean(a(1:5,1)), C(1,2)=mean(a(1:5,2)) , C(2,1)=mean(a(6:8,1)), C(2,2)=mean(a(6:8,2)) … and so on

Best Answer

Use accumarray, as illustrated in this recent thread, very similar to yours

https://www.mathworks.com/matlabcentral/answers/370598-code-optimization-by-avoiding-loops#answer_294282

Related Solutions

MATLAB: Finding average between TFunct1,TFunct2,TFunct3

Hi,

how about this:

TFunct=zeros(1700,1); % or whatever
for i = 1 : 17000
TFunct(i,1)=mean([TFunct1(i,1),TFunct2(i,1),TFunct3(i,1)]);
end

or without a loop you can use this:

>> A=[1 2;2 3;3 4;4 5;5 6]
A =
       1     2
       2     3
       3     4
       4     5
       5     6
  >> B=[2 3;3 4;4 5;5 6;6 7]
B =
       2     3
       3     4
       4     5
       5     6
       6     7
  >> C=[3 4;4 5;5 6;6 7;7 8]
C =
       3     4
       4     5
       5     6
       6     7
       7     8
  >> D=[A(:,1)';B(:,1)';C(:,1)']
D =
       1     2     3     4     5
       2     3     4     5     6
       3     4     5     6     7
>> mean(D)
ans =
       2     3     4     5     6

MATLAB: How to count average value from each row of matrix

 mean(A, 2)

will you average by row.

Best Answer

Related Solutions

MATLAB: Finding average between TFunct1,TFunct2,TFunct3

MATLAB: How to count average value from each row of matrix

Related Question