Add a function to the MC simulator to find the most likely set of results resulting...

diff --git a/mcwordfeud.cpp b/mcwordfeud.cpp
index 63b98e1ae33f578ca63aa4754a6b5ca15a1cb7b0..3b55f01c88ee5dc4433d1322a8c49209dd884d14 100644 (file)
--- a/mcwordfeud.cpp
+++ b/mcwordfeud.cpp
@@ -17,6 +17,11 @@ using namespace Eigen;
 
 #define MAX_PLAYERS 16
 
+enum OutputMode {
+       PROBABILITY_MATRIX = 0,
+       MOST_LIKELY_MATCHING = 1,
+};
+
 float match_stddev = 70.0f;
 
 struct player {
@@ -70,6 +75,20 @@ float draw_gaussian(float mu, float stddev)
 int main(int argc, char **argv)
 {
        int trials = atoi(argv[1]);
+       OutputMode output_mode;
+       int match_player_num = -1, match_position = -1;
+       if (argc >= 3) {
+               match_player_num = atoi(argv[2]);
+               match_position = atoi(argv[3]);
+               output_mode = MOST_LIKELY_MATCHING;
+       } else {
+               output_mode = PROBABILITY_MATRIX;
+       }
+
+       // For most likely matching.
+       bool has_mlm = false;
+       double mlm_likelihood = 0.0f;
+       int mlm_scores[MAX_PLAYERS][MAX_PLAYERS];
 
        if (scanf("%f", &match_stddev) != 1) {
                fprintf(stderr, "Could't read match stddev\n");
@@ -204,16 +223,62 @@ int main(int argc, char **argv)
 
                // order by points and then margin
                sort(stats, stats + num_players, highest_ranking());
-               for (int j = 0; j < num_players; ++j) {
-                       ++placements[stats[j].player_index][j];
+
+               if (output_mode == PROBABILITY_MATRIX) {
+                       for (int j = 0; j < num_players; ++j) {
+                               ++placements[stats[j].player_index][j];
+                       }
+               }
+               if (output_mode == MOST_LIKELY_MATCHING) {
+                       if (stats[match_position].player_index != match_player_num) {
+                               continue;
+                       }
+
+                       // compute the log-likelihood of this situation (ignoring the constant terms)
+                       double llh = 0.0f;
+
+                       // strength of all players (ignore the constant terms)
+                       for (int p = 0; p < num_players; ++p) {
+                               llh -= drawn_normals(p) * drawn_normals(p) * 0.5f;
+                       }
+
+                       // all the matches
+                       for (int pl1 = 0; pl1 < num_players; ++pl1) {
+                               for (int pl2 = pl1 + 1; pl2 < num_players; ++pl2) {
+                                       if (has_scores[pl1][pl2]) {
+                                               continue;
+                                       }
+                                       float mu = drawn_ratings(pl1) - drawn_ratings(pl2);
+                                       float z = (scores[pl1][pl2] - mu) / match_stddev;
+                                       llh -= z * z * 0.5f;
+                               }
+                       }
+
+                       if (!has_mlm || llh > mlm_likelihood) {
+                               has_mlm = true;
+                               mlm_likelihood = llh;
+                               memcpy(mlm_scores, scores, sizeof(mlm_scores));
+                       }
                }
        }
 
-       for (int i = 0; i < num_players; ++i) {
-               printf("%-15s", players[i].c_str());
-               for (int j = 0; j < num_players; ++j) {
-                       printf(" %5d", placements[i][j]);
+       if (output_mode == PROBABILITY_MATRIX) {
+               for (int i = 0; i < num_players; ++i) {
+                       printf("%-15s", players[i].c_str());
+                       for (int j = 0; j < num_players; ++j) {
+                               printf(" %5d", placements[i][j]);
+                       }
+                       printf("\n");
+               }
+       }
+       if (output_mode == MOST_LIKELY_MATCHING && has_mlm) {
+               for (int pl1 = 0; pl1 < num_players; ++pl1) {
+                       for (int pl2 = pl1 + 1; pl2 < num_players; ++pl2) {
+                               if (has_scores[pl1][pl2]) {
+                                       continue;
+                               }
+                               printf("%s %s %d\n", players[pl1].c_str(), players[pl2].c_str(), mlm_scores[pl1][pl2]);
+                       }
                }
-               printf("\n");
        }
 }