Concurrency with loops

Question

it's me again. So i have a problem with concurrency in Ada. Basically part of my program looks like that:

for i in 1..it loop

    for x in 1..A loop
        for y in 1..B
            --tab(x,y):=...
        end loop;
    end loop;

    for x in 1..A loop
        for y in 1..B
            --tab(x,y):=...
        end loop;
    end loop;

end loop;

Inside this loops are some calculations. What i intend to do is to make these two 'inside' loops work concurrently. Either one element from loop 1, then one element element from loop 2 or little less 'symmetric'. But generally i want it to look like that: first iteration, two 'inside' loops work concurrently, all operations finish, iteration finishes. Second iteration same and so on.. My questions is: can i do it with ENTRY and ACCEPT statements? Or will this require something more? If You could just point me the right solution, because i've seen many examples but none suiting my issue.

Answer 1

If the two inner loops really don't share any data, you can do it loke this:

task First;
task Second;

task body First is
   ...
begin
   for i in 1 .. it loop
      for x in 1 .. A loop
         for y in 1 .. B loop
             ...
         end loop;
      end loop;
   end loop;
end First;

task body Second is
   ...
begin
   for i in 1 .. it loop
      for x in 1 .. A loop
         for y in 1 .. B loop
             ...
         end loop;
      end loop;
   end loop;
end Second;

Answer 2

You may want to limit the amount of tasks to the amount of cores supported by the system. See this example on calculating pi: https://github.com/AdaDoom3/OldStuff/blob/master/time_pi.adb