Addition of time series extracted from a file

Hi, Here is the code

p=zeros(q,r);
p(q,i)=sum(x.Time_Series(:,s(i,1))));

Please note the following points. 1. x.Time_Series gives me the time series of 688 taps(points). Each tap has 49792 readings which can be positive or negative numbers. Therefore, x.Time_Series is 49792*688 matrix. 2. I require readings of only 9 taps and these are extracted in s. s is 1*9 matrix and represents the column no of each tap 66 68 69 79 . . 80 3. value of r is 9.

My Problem: I want to make a single matrix p which stores the sum of corresponding elements of matrices of 9 taps(points) given in s. When I run the above code, it says "Subscript indices must either be real positive integers or logicals".

Answer 1

[per isakson]

Study this example:

    M   = randn( 1000, 10 );
    ix  = [ 3, 5, 7 ];
    S = sum( M(:,ix), 1 );

it returns

    >> S
    S =
       38.2749   30.5600    3.8223

which are the sums of column number 3, 5 and 7