Why won't this for loop move to the next variable?

On the first pass, everything is fine. i = 49, j = 1, k = 1112. On the second pass, i and j move to the next variables (50 and 18), but k stays at 1112. It does the same thing on the third and fourth pass. Can someone please point out my error? My sincerest gratitude for reading.

for i = 49:52
    expiry=find(vifDate==expDate(i));
    for j = [1; 18; 43; 63]
        vifCls1 = vifCls(j:expiry);
        for k = [1112; 1129; 1154; 1174]
            consolFut1 = consolFut(k:expDateIdx(i),i);
            arbVIF=vifCls1-consolFut1;
        end
    end
end

Answer 1

[Thorsten]

I you code only i cycles to the values 49,50, ..., while j and k are always a 4x1 vector [1; 18; 43; 63] and k = [1112; 1129; 1154; 1174]. You have to use row vectors in the for loop:

for j = [1 18 43 63]
  % some code
  for k = [1112 1129 1154 1174]

Answer 2

[Star Strider]

Your loops probably are incrementing, but because of the way you created your indices, you’re just not seeing it.

Consider:

ix = 1;
for i = 49:52
    for j = [1; 18; 43; 63]'
        for k = [1112; 1129; 1154; 1174]'
            Q(ix,:) = [i j k];
            ix = i + 1;
        end
    end
end

figure(1)
stem3(Q(:,1), Q(:,2), Q(:,3))
grid on
xlabel('i')
ylabel('j')
zlabel('k')

The plot shows that all the loops are incrementing.

[Thorsten]

Your example works because you use row vectors for the indices (or transposed column vectors, to be more precise). Cary's code does not work, because she uses column vectors; it is not a matter of "not seeing it".

[Star Strider]

The column vectors quite definitely do not work (that I found surprising).

I transposed them to demonstrate that even if the loops would increment, it will be difficult to see the result because of the inefficient ways the loops are indexed.