for loop problem

for i=1:a:20

    idx=find(consecutiveDiff(:,1)==val(i));

    a=numel(idx);

end

i need to increment the value i as the value of a is changed. in first execute if a=5 the value of i becomes 2 not 1+5=6 . why ? can any body help?

Answer 1

[Jan]

when the line for i = 1:a:20 is executed it uses the value of a as it is then known, which is probably 1.

You will need something like this:

i = 1;
while i<=20
  idx = find(consecutiveDiff(:,1)==val(i));
  a = numel(idx);
  i = i + a;
end