reward = [1 2 3; 3 4 5; 5 6 7]; cs = 1;
Check the output of your code one part at a time
>> reward(cs,:)
ans =
1 2 3
The above line output cs=1 row of matrix reward. Next we use compairson operator
>> reward(cs,:)>0
ans =
1×3 logical array
1 1 1
This line find which elements are greater than 0. As you can see, all of them are above zero so we get [1 1 1]. Next
>> find(reward(cs,:)>0)
ans =
1 2 3
The find() function return the index of all elements that are non-zero.
For example,
>> find([1 2 0 1 0])
ans =
1 2 4
It shows that element number 1, 2, and 4 are non-zero.
