Infinite while loop for iterating data

I have a data-set that has the following form

      MMSI  Latitude    Longitude      Date  Time  Time (decimal)
      277333444  59.8564      30.497      04-08-12  09:49  589
      241025000  37.3462      24.8713      04-08-12  09:49  589
      636012774  35.7931      28.7227      04-08-12  11:29  680
      248681000  36.9327      27.3042      04-08-12  11:52  703
      312847000  35.3429      28.5582      04-08-12  11:52  703
      239737000  36.4827      27.9405      04-08-12  11:52  703
      200  36.7672      34.6444      04-08-12  12:52    763
      237071900  36.7778      24.578      04-08-12  12:52  763

where the MMSI is the ID of different ships.I want to compute the distance between two different points and get as a result the MMSIs involved as well as the times. I've written the following code, which does not work as I described.

for i = 1:length(MM(:,5))
        t = MM(i,5);
        ind1 = i;
        length(ind1);
        lat1 = lat(ind1);
        lon1 = lon(ind1);

          while (t <= (MM(i,5)+5))
              for j = 2:length(MM(j,1))
                  ind2 = j;
                  length(ind2);
                  lat2 = lat(ind2);
                  lon2 = lon(ind2);
                  w = MM(j,8);            
              end

              dis = distance(lat1, lon1, lat2, lon2);
              t = t+1;
          end

          if dis<=1

              contact = [ind1, ind2, t, w];
          end
        end

This code essentially does the following:

for i = 1:length(MM(:,5)) 
    ind1 = i;
    lat1 = lat(ind1);
    lon1 = lon(ind1);

      ind2 = MM(2,1);
      lat2 = lat(ind2);
      lon2 = lon(ind2);
      w = MM(d,5);
      t = MM(i,5)+5+1

      dis = distance(lat1, lon1, lat2, lon2);

      if dis<=1
          contact = [ind1, ind2, t, w];
      end
  end

and the while loop becomes an infinite loop. How can I write a while loop, in which I will take the elements from the second row and below and compute the distance from the element in the first row as long as the condition in the while is true? And after the distance is computed I want to get the contact matrix which contains the two different MMSIs and the times

Answer 1

[Eng. Fredius Magige]

Hi you data MM not involved and should be called for execution MM=[] % being known as first matrix

I think for i = 1:length(MM(:,5)) be for i = 1:length(MM(:,6))

[Vasiliki Charisi]

Yes, it should be for

i=1:length(MM(:,6))

I didn't noticed it when I wrote the question. But I do not understand what do you mean by:data MM not involved and should be called for execution MM=[] % being known as first matrix. Could you explain me please what you mean?

Answer 2

[Thorsten]

You can compute the distances between all pairs as

 allpairs = nchoosek(1:8,2);
 for i=1:numel(allpairs)
   i1 = allpairs(i,1); i2 = allpairs(i,2);
   d(i) = distance(lat(i1), lon(i1), lat(i2), lon(i2));
 end

And select identifiers and time

ind = d > 1;
i1 = allpairs(ind,1); i2 = allpairs(ind,2);
IDandTime = [mmsi(i1) mmsi(i2) time(i1) time(i2) ];