+static uint32_t fac (uint32_t x)
+{
+ if (1 >= x)
+ {
+ return x;
+ }
+ return x * fac (x - 1);
+}
+
+static uint32_t binom (uint32_t n, uint32_t k)
+{
+ //GNUNET_assert (n >= k);
+ if (k > n) return 0;
+ if (0 > n) return 0;
+ if (0 > k) return 0;
+ if (0 == k) return 1;
+ return fac (n)
+ /
+ fac(k) * fac(n - k);
+}
+
+/**
+ * @brief is b in view of a?
+ *
+ * @param a
+ * @param b
+ *
+ * @return
+ */
+static int is_in_view (uint32_t a, uint32_t b)
+{
+ uint32_t i;
+ for (i = 0; i < rps_peers[a].cur_view_count; i++)
+ {
+ if (0 == memcmp (rps_peers[b].peer_id,
+ &rps_peers[a].cur_view[i],
+ sizeof (struct GNUNET_PeerIdentity)))
+ {
+ return GNUNET_YES;
+ }
+ }
+ return GNUNET_NO;
+}
+
+static uint32_t get_idx_of_pid (const struct GNUNET_PeerIdentity *pid)
+{
+ uint32_t i;
+
+ for (i = 0; i < num_peers; i++)
+ {
+ if (0 == memcmp (pid,
+ rps_peers[i].peer_id,
+ sizeof (struct GNUNET_PeerIdentity)))
+ {
+ return i;
+ }
+ }
+ //return 0; /* Should not happen - make compiler happy */
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "No known _PeerIdentity %s!\n",
+ GNUNET_i2s_full (pid));
+ GNUNET_assert (0);
+}
+
+/**
+ * @brief Counts number of peers in view of a that have b in their view
+ *
+ * @param a
+ * @param uint32_tb
+ *
+ * @return
+ */
+static uint32_t count_containing_views (uint32_t a, uint32_t b)
+{
+ uint32_t i;
+ uint32_t peer_idx;
+ uint32_t count = 0;
+
+ for (i = 0; i < rps_peers[a].cur_view_count; i++)
+ {
+ peer_idx = get_idx_of_pid (&rps_peers[a].cur_view[i]);
+ if (GNUNET_YES == is_in_view (peer_idx, b))
+ {
+ count++;
+ }
+ }
+ return count;
+}
+
+/**
+ * @brief Computes the probability for each other peer to be selected by the
+ * sampling process based on the views of all peers
+ *
+ * @param peer_idx index of the peer that is about to sample
+ */
+static void compute_probabilities (uint32_t peer_idx)
+{
+ //double probs[num_peers] = { 0 };
+ double probs[num_peers];
+ size_t probs_as_str_size = (num_peers * 10 + 1) * sizeof (char);
+ char *probs_as_str = GNUNET_malloc (probs_as_str_size);
+ char *probs_as_str_cpy;
+ uint32_t i;
+ double prob_push;
+ double prob_pull;
+ uint32_t view_size;
+ uint32_t cont_views;
+ uint32_t number_of_being_in_pull_events;
+ int tmp;
+ uint32_t count_non_zero_prob = 0;
+
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "Computing probabilities for peer %" PRIu32 "\n", peer_idx);
+ /* Firstly without knowledge of old views */
+ for (i = 0; i < num_peers; i++)
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "\tfor peer %" PRIu32 ":\n", i);
+ view_size = rps_peers[i].cur_view_count;
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "\t\tview_size: %" PRIu32 "\n", view_size);
+ /* For peer i the probability of being sampled is
+ * evenly distributed among all possibly observed peers. */
+ /* We could have observed a peer in three cases:
+ * 1. peer sent a push
+ * 2. peer was contained in a pull reply
+ * 3. peer was in history (sampler) - ignored for now */
+ /* 1. Probability of having received a push from peer i */
+ if ((GNUNET_YES == is_in_view (i, peer_idx)) &&
+ (1 <= (0.45 * view_size)))
+ {
+ prob_push = 1.0 * binom (0.45 * view_size, 1)
+ /
+ binom (view_size, 0.45 * view_size);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "\t\t%" PRIu32 " is in %" PRIu32 "'s view, prob: %f\n",
+ peer_idx,
+ i,
+ prob_push);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "\t\tposs choices from view: %" PRIu32 ", containing i: %" PRIu32 "\n",
+ binom (view_size, 0.45 * view_size),
+ binom (0.45 * view_size, 1));
+ } else {
+ prob_push = 0;
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "\t\t%" PRIu32 " is not in %" PRIu32 "'s view, prob: 0\n",
+ peer_idx,
+ i);
+ }
+ /* 2. Probability of peer i being contained in pulls */
+ view_size = rps_peers[peer_idx].cur_view_count;
+ cont_views = count_containing_views (peer_idx, i);
+ number_of_being_in_pull_events =
+ (binom (view_size, 0.45 * view_size) -
+ binom (view_size - cont_views, 0.45 * view_size));
+ if (0 != number_of_being_in_pull_events)
+ {
+ prob_pull = number_of_being_in_pull_events
+ /
+ (1.0 * binom (view_size, 0.45 * view_size));
+ } else
+ {
+ prob_pull = 0;
+ }
+ probs[i] = prob_push + prob_pull - (prob_push * prob_pull);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "\t\t%" PRIu32 " has %" PRIu32 " of %" PRIu32
+ " peers in its view who know %" PRIu32 " prob: %f\n",
+ peer_idx,
+ cont_views,
+ view_size,
+ i,
+ prob_pull);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "\t\tnumber of possible pull combinations: %" PRIu32 "\n",
+ binom (view_size, 0.45 * view_size));
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "\t\tnumber of possible pull combinations without %" PRIu32
+ ": %" PRIu32 "\n",
+ i,
+ binom (view_size - cont_views, 0.45 * view_size));
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "\t\tnumber of possible pull combinations with %" PRIu32
+ ": %" PRIu32 "\n",
+ i,
+ number_of_being_in_pull_events);
+
+ if (0 != probs[i]) count_non_zero_prob++;
+ }
+ /* normalize */
+ if (0 != count_non_zero_prob)
+ {
+ for (i = 0; i < num_peers; i++)
+ {
+ probs[i] = probs[i] * (1.0 / count_non_zero_prob);
+ }
+ } else {
+ for (i = 0; i < num_peers; i++)
+ {
+ probs[i] = 0;
+ }
+ }
+ /* str repr */
+ for (i = 0; i < num_peers; i++)
+ {
+ probs_as_str_cpy = GNUNET_strndup (probs_as_str, probs_as_str_size);
+ tmp = GNUNET_snprintf (probs_as_str,
+ probs_as_str_size,
+ "%s %7.6f", probs_as_str_cpy, probs[i]);
+ GNUNET_free (probs_as_str_cpy);
+ GNUNET_assert (0 <= tmp);
+ }
+
+ to_file_w_len (rps_peers[peer_idx].file_name_probs,
+ probs_as_str_size,
+ probs_as_str);
+ GNUNET_free (probs_as_str);
+}
+
+/**
+ * @brief This counts the number of peers in which views a given peer occurs.
+ *
+ * It also stores this value in the rps peer.
+ *
+ * @param peer_idx the index of the peer to count the representation
+ *
+ * @return the number of occurrences
+ */
+static uint32_t count_peer_in_views_2 (uint32_t peer_idx)
+{
+ uint32_t i, j;
+ uint32_t count = 0;
+
+ for (i = 0; i < num_peers; i++) /* Peer in which view is counted */
+ {
+ for (j = 0; j < rps_peers[i].cur_view_count; j++) /* entry in view */
+ {
+ if (0 == memcmp (rps_peers[peer_idx].peer_id,
+ &rps_peers[i].cur_view[j],
+ sizeof (struct GNUNET_PeerIdentity)))
+ {
+ count++;
+ break;
+ }
+ }
+ }
+ rps_peers[peer_idx].count_in_views = count;
+ return count;
+}
+
+static uint32_t cumulated_view_sizes ()
+{
+ uint32_t i;
+
+ view_sizes = 0;
+ for (i = 0; i < num_peers; i++) /* Peer in which view is counted */
+ {
+ view_sizes += rps_peers[i].cur_view_count;
+ }
+ return view_sizes;
+}
+
+static void count_peer_in_views (uint32_t *count_peers)
+{
+ uint32_t i, j;
+
+ for (i = 0; i < num_peers; i++) /* Peer in which view is counted */
+ {
+ for (j = 0; j < rps_peers[i].cur_view_count; j++) /* entry in view */
+ {
+ if (0 == memcmp (rps_peers[i].peer_id,
+ &rps_peers[i].cur_view[j],
+ sizeof (struct GNUNET_PeerIdentity)))
+ {
+ count_peers[i]++;
+ }
+ }
+ }
+}
+
+void compute_diversity ()
+{
+ uint32_t i;
+ /* ith entry represents the numer of occurrences in other peer's views */
+ uint32_t *count_peers = GNUNET_new_array (num_peers, uint32_t);
+ uint32_t views_total_size;
+ double expected;
+ /* deviation from expected number of peers */
+ double *deviation = GNUNET_new_array (num_peers, double);
+
+ views_total_size = 0;
+ expected = 0;
+
+ /* For each peer count its representation in other peer's views*/
+ for (i = 0; i < num_peers; i++) /* Peer to count */
+ {
+ views_total_size += rps_peers[i].cur_view_count;
+ count_peer_in_views (count_peers);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "Counted representation of %" PRIu32 "th peer [%s]: %" PRIu32"\n",
+ i,
+ GNUNET_i2s (rps_peers[i].peer_id),
+ count_peers[i]);
+ }
+
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "size of all views combined: %" PRIu32 "\n",
+ views_total_size);
+ expected = ((double) 1/num_peers) * views_total_size;
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "Expected number of occurrences of each peer in all views: %f\n",
+ expected);
+ for (i = 0; i < num_peers; i++) /* Peer to count */
+ {
+ deviation[i] = expected - count_peers[i];
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "Deviation from expectation: %f\n", deviation[i]);
+ }
+ GNUNET_free (count_peers);
+ GNUNET_free (deviation);
+}
+
+void print_view_sizes()
+{
+ uint32_t i;
+
+ for (i = 0; i < num_peers; i++) /* Peer to count */
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "View size of %" PRIu32 ". [%s] is %" PRIu32 "\n",
+ i,
+ GNUNET_i2s (rps_peers[i].peer_id),
+ rps_peers[i].cur_view_count);
+ }
+}
+
+void all_views_updated_cb()
+{
+ compute_diversity();
+ print_view_sizes();
+}
+
+void view_update_cb (void *cls,
+ uint64_t view_size,
+ const struct GNUNET_PeerIdentity *peers)
+{
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "View was updated (%" PRIu64 ")\n", view_size);
+ struct RPSPeer *rps_peer = (struct RPSPeer *) cls;
+ to_file ("/tmp/rps/view_sizes.txt",
+ "%" PRIu64 " %" PRIu32 "",
+ rps_peer->index,
+ view_size);
+ for (int i = 0; i < view_size; i++)
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "\t%s\n", GNUNET_i2s (&peers[i]));
+ }
+ GNUNET_array_grow (rps_peer->cur_view,
+ rps_peer->cur_view_count,
+ view_size);
+ //*rps_peer->cur_view = *peers;
+ GNUNET_memcpy (rps_peer->cur_view,
+ peers,
+ view_size * sizeof (struct GNUNET_PeerIdentity));
+ to_file ("/tmp/rps/count_in_views.txt",
+ "%" PRIu64 " %" PRIu32 "",
+ rps_peer->index,
+ count_peer_in_views_2 (rps_peer->index));
+ cumulated_view_sizes();
+ if (0 != view_size)
+ {
+ to_file ("/tmp/rps/repr.txt",
+ "%" PRIu64 /* index */
+ " %" PRIu32 /* occurrence in views */
+ " %" PRIu32 /* view sizes */
+ " %f" /* fraction of repr in views */
+ " %f" /* average view size */
+ " %f" /* prob of occurrence in view slot */
+ " %f" "", /* exp frac of repr in views */
+ rps_peer->index,
+ count_peer_in_views_2 (rps_peer->index),
+ view_sizes,
+ count_peer_in_views_2 (rps_peer->index) / (view_size * 1.0), /* fraction of representation in views */
+ view_sizes / (view_size * 1.0), /* average view size */
+ 1.0 /view_size, /* prob of occurrence in view slot */
+ (1.0/view_size) * (view_sizes/view_size) /* expected fraction of repr in views */
+ );
+ }
+ compute_probabilities (rps_peer->index);
+ all_views_updated_cb();
+}
+
+static void
+pre_profiler (struct RPSPeer *rps_peer, struct GNUNET_RPS_Handle *h)
+{
+ rps_peer->file_name_probs =
+ store_prefix_file_name (rps_peer->peer_id, "probs");
+ GNUNET_RPS_view_request (h, 0, view_update_cb, rps_peer);
+}
+
+void write_final_stats (void){
+ uint32_t i;
+
+ for (i = 0; i < num_peers; i++)
+ {
+ to_file ("/tmp/rps/final_stats.dat",
+ "%" PRIu32 " " /* index */
+ "%s %" /* id */
+ PRIu64 " %" /* rounds */
+ PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" PRIu64 " %" /* blocking */
+ PRIu64 " %" PRIu64 " %" PRIu64 " %" /* issued */
+ PRIu64 " %" PRIu64 " %" PRIu64 " %" /* sent */
+ PRIu64 " %" PRIu64 " %" PRIu64 /* recv */,
+ i,
+ GNUNET_i2s (rps_peers[i].peer_id),
+ rps_peers[i].num_rounds,
+ rps_peers[i].num_blocks,
+ rps_peers[i].num_blocks_many_push,
+ rps_peers[i].num_blocks_no_push,
+ rps_peers[i].num_blocks_no_pull,
+ rps_peers[i].num_blocks_many_push_no_pull,
+ rps_peers[i].num_blocks_no_push_no_pull,
+ rps_peers[i].num_issued_push,
+ rps_peers[i].num_issued_pull_req,
+ rps_peers[i].num_issued_pull_rep,
+ rps_peers[i].num_sent_push,
+ rps_peers[i].num_sent_pull_req,
+ rps_peers[i].num_sent_pull_rep,
+ rps_peers[i].num_recv_push,
+ rps_peers[i].num_recv_pull_req,
+ rps_peers[i].num_recv_pull_rep);
+ }
+}
+