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52 | procedure main(argc, argv[]):
if argc = 3 then
// We need a referee, and two processes for each team -> odd number: 2t + 1
if process_count >= 3 and process_count % 2 = 1 then
declare constant team_count = div(process_count - 1, 2)
declare constant stage1_delay = integer(argv[1])
declare constant stage2_delay = integer(argv[2])
if process_number = 0 then
referee(team_count)
else if process_number <= team_count then
run_stage1(stage1_delay, process_number, team_count)
else
run_stage2(stage2_delay, process_number, team_count)
end if
else
print "error: process count must be odd and greater than 3"
end if
else
print "usage: relay_race_dist stage1_delay stage2_delay"
end if
end procedure
procedure run_stage1(stage1_delay, process_number, team_count):
wait_barrier()
delay(stage1_delay)
declare constant peer = process_number + team_count
declare baton := true
send(&baton, 1, peer)
end function
procedure run_stage2(stage2_delay, process_number, team_count):
wait_barrier()
declare peer := process_number - team_count
declare baton := false
receive(&baton, 1, peer)
delay(stage2_delay)
send(&peer, 1, 0)
end procedure
procedure referee(team_count):
declare constant start_time = wall_time()
wait_barrier()
declare place := 0
for index := 0 to team_count do
declare team := 0
receive(&team, 1, any_process)
declare constant elapsed = wall_time() - start_time
place := place + 1
print "Place ", place, ": team ", team, " in ", elapsed, "s"
end for
end procedure
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