A Programs for ReachabilityA

while (1) { with (s1) /* send r to 2d shape */ where (s1mask) pcoord(0)]]0]conn = r; with (s2) where (s2mask) { conn = copy_spread(&conn;, 1, 0); /* spread */ conn &= e; /* combine */ reduce(&conn;, conn, 0, /* reduce */ CMC_combiner_logior, 0); where (pcoord(0)==0) pcoord(1)]temp = conn; /* return result */ } with (s1) { /* stop if r hasn't changed */ if (&=(temp==r)) break; r = temp; } } CM_timer_stop(1); CM_timer_print(1); } 25 C r contains the nodes that node 1 is connected to r(1:n) = e(1,1:n) call CM_timer_clear(1) call CM_timer_start(1) do while (.TRUE.) temp = any(spread(r, DIM = 2, NCOPIES = n) .and. e, $ DIM = 1) if (all(temp .eqv. r)) then goto 100 end if r = temp end do 100 continue call CM_timer_stop(1) call CM_timer_print(1) end A.3 Reachability in C #include #include #include #define N 512 #define N_PROCS 8192 int main(int argc,char *argvv]) { shape N_PROCS]s1; /* shapes must have more than 512 elements */ shape N]]N]s2; /* 512*512 > N_PROCS, so no padding needed */ int:s2 e, conn, s2mask; int:s1 r, temp, s1mask; /* initialize e so each node is connected to next higher node */ with (s2) { e = 0; pcoord(0)]]pcoord(0)]e = 1; where (pcoord(0) < (N-1)) pcoord(0)]]pcoord(0)+1]e = 1; } /* these masks prevent collisions in sends */ with (s1) s1mask = (pcoord(0)<N); with (s2) s2mask = (pcoord(0)<N && pcoord(1)<N); /* rri] is true if node 0 is connected to node i */ with (s2) where (s2mask & pcoord(0)==0) pcoord(1)]r = e;