Loop if for one j

I'm writing a script to simulate the movement of some particles, so I'm working with discrete timesteps i in a for-loop. Inside this loop, I have another for-loop to change position etc. of every particle k. Now, I want to check for every k if there is any of the other particles (for loop over particle j) wich comes too close because than both will annihilate(disappear) which means the new position etc. for k (and j) doesn't need to be computed anymore.

So my question is: how do I check FOR every 1<k<m IF there exist a 1<j<m, j~=k which satisfies certain requirements and IF that's the case move on directly to k+1? ELSE, so if there's no j with the requirements for this k, proceed to the calculation of r(k,i+1)... via a specific algorithm before going to particle k+1.

for i=1:n %timestep
for k=1:m %particle
if isnan(rx(k,i))==1 %I'm checking if it still exists, if not don't do anything and go to the next k
else
      for j=1:m %other particles 
          if isnan(rx(j,i))==0     %check if it still exists
              if j~=k
                  d(k,j)=(rx(k,i)-rx(j,i))^2+(ry(k,i)-ry(j,i))^2;
                  if d(k,j)<1.5*z0 && s(k)+s(j)==0  %IF THAT'S THE CASE I WANT TO INCREASE K BY ONE IMMEDIATELY

                    end
                ... some other stuff about interaction k and j...
                end
                ... some more irrelevant stuff...
                end
            end
        end
        ... calculate rx(k,i+1) etc ... 
       end
    end
  end

[dpb]

Would be far simpler if had the basic code to look at, but sounds like you're looking for

doc continue  % you may find _break_ of interest, too...

[Wouter]

@dpb if I try continue, it just moves to the next j but I want to the next k. And if I try break, it moves to the rest of the code behind the j-loop but still for that k.

[Patrik Ek]

while j<some_value && condition?

Answer 1

[Chris C]

You need to break out of the j-loop upon that condition and then condition a continue statement within the k-loop.