Fix some extreme cases in bayes.

diff --git a/src/libstat/classifiers/bayes.c b/src/libstat/classifiers/bayes.c
index 6c17e90caa5a36d93f21fd9de9bb7dc33dc3f895..03512f771b5a93f3bc392ec129ca8a7559ce1e30 100644 (file)
--- a/src/libstat/classifiers/bayes.c
+++ b/src/libstat/classifiers/bayes.c
@@ -167,43 +167,37 @@ bayes_classify (struct classifier_ctx * ctx,
                g_tree_foreach (input, bayes_classify_callback, rt);
        }
        else {
-
-               if (rt->spam_prob == 0) {
-                       final_prob = 0;
+               h = 1 - inv_chi_square (-2. * rt->spam_prob,
+                               2 * rt->processed_tokens);
+               s = 1 - inv_chi_square (-2. * rt->ham_prob,
+                               2 * rt->processed_tokens);
+
+               if (isfinite (s) && isfinite (h)) {
+                       final_prob = (s + 1.0 - h) / 2.;
+                       msg_debug ("<%s> got ham prob %.2f -> %.2f and spam prob %.2f -> %.2f,"
+                                       " %L tokens processed of %ud total tokens",
+                                       task->message_id, rt->ham_prob, h, rt->spam_prob, s,
+                                       rt->processed_tokens, g_tree_nnodes (input));
                }
                else {
-                       h = 1 - inv_chi_square (-2. * rt->spam_prob,
-                                       2 * rt->processed_tokens);
-                       s = 1 - inv_chi_square (-2. * rt->ham_prob,
-                                       2 * rt->processed_tokens);
-
-                       if (isfinite (s) && isfinite (h)) {
-                               final_prob = (s + 1.0 - h) / 2.;
-                               msg_debug ("<%s> got ham prob %.2f -> %.2f and spam prob %.2f -> %.2f,"
-                                               " %L tokens processed of %ud total tokens",
-                                               task->message_id, rt->ham_prob, h, rt->spam_prob, s,
-                                               rt->processed_tokens, g_tree_nnodes (input));
+                       /*
+                        * We have some overflow, hence we need to check which class
+                        * is NaN
+                        */
+                       if (isfinite (h)) {
+                               final_prob = 1.0;
+                               msg_debug ("<%s> spam class is overflowed, as we have no"
+                                               " ham samples", task->message_id);
+                       }
+                       else if (isfinite (s)){
+                               final_prob = 0.0;
+                               msg_debug ("<%s> ham class is overflowed, as we have no"
+                                               " spam samples", task->message_id);
                        }
                        else {
-                               /*
-                                * We have some overflow, hence we need to check which class
-                                * is NaN
-                                */
-                               if (isfinite (h)) {
-                                       final_prob = 1.0;
-                                       msg_debug ("<%s> spam class is overflowed, as we have no"
-                                                       " ham samples", task->message_id);
-                               }
-                               else if (isfinite (s)){
-                                       final_prob = 0.0;
-                                       msg_debug ("<%s> spam class is overflowed, as we have no"
-                                                       " spam samples", task->message_id);
-                               }
-                               else {
-                                       final_prob = 0.5;
-                                       msg_warn ("<%s> spam and ham classes are both overflowed",
-                                                       task->message_id);
-                               }
+                               final_prob = 0.5;
+                               msg_warn ("<%s> spam and ham classes are both overflowed",
+                                               task->message_id);
                        }
                }
 
@@ -228,7 +222,8 @@ bayes_classify (struct classifier_ctx * ctx,
 
                        if (selected_st == NULL) {
                                msg_err (
-                                       "unexpected classifier error: cannot select desired statfile");
+                                       "unexpected classifier error: cannot select desired statfile, "
+                                       "prob: %.4f", final_prob);
                        }
                        else {
                                /* Correctly scale HAM */