Summation after looping

I got a problem with summation after looping. Here is the problem :

------------------------------------------

for ri = 0:3

        if ri == 0
           mi = 1
        elseif i > 0
           mi = 1
        end  
end

r = sum(ri)

------------------------------------------

I'm expecting the result from r was 6 (0+1+2+3) but its result was 3. I think the sum command only read the last ri which is 3 and neglecting the other ri.

Any answer will be appreciated. Thanks!

Answer 1

[Matt Kindig]

When you use the 'for' statement, you iteratively set ri to each of the values 0, 1, 2, 3. Thus ri only contains 3 after the loop. Instead, assign ri=0:3 to a different variable and have the for loop iterate over that.

For example,

    rr = 0:3;
    for ri=rr,
       if ri == 0
             mi = 1
          elseif i > 0
             mi = 1
          end  
    end
    r = sum(rr);  %this will be 6

[Fajar Muharrom]

Thank you Matt Kindig :))

Answer 2

[Fajar Muharrom]

1st problem was solved. but i got another one, it's similar with the 1st one. I couldn't get the right sum.

-----------------------------------------

i = 0:3;

rx = i

ry = i

rz = i

for r = i

    ri = [r r r]        
        if r == 0
           mi = 1
        elseif r > 0
           mi = 1
        end
    ri_mi = ri*mi
end

m = 3*mi

rC= 1/m*[sum(ri_mi,1)]

-----------------------------------------

in this case the sum of ri_mi only take the last mi_ri from the looping command. Do you have any idea to solve this problem, Matt Kindig? I will very appreciate it.