directly take pairwise prob as multiclass prob when nr_class is 2

Author: Kevin Lee

java/libsvm/svm.m4

@@ -2428,7 +2428,13 @@ public class svm {
 					pairwise_prob[j][i]=1-pairwise_prob[i][j];
 					k++;
 				}
-			multiclass_probability(nr_class,pairwise_prob,prob_estimates);
+			if (nr_class == 2)
+			{
+				prob_estimates[0] = pairwise_prob[0][1];
+				prob_estimates[1] = pairwise_prob[1][0];
+			}
+			else
+				multiclass_probability(nr_class,pairwise_prob,prob_estimates);
 
 			int prob_max_idx = 0;
 			for(i=1;i<nr_class;i++)

svm.cpp

@@ -2612,7 +2612,13 @@ double svm_predict_probability(
 				pairwise_prob[j][i]=1-pairwise_prob[i][j];
 				k++;
 			}
-		multiclass_probability(nr_class,pairwise_prob,prob_estimates);
+		if (nr_class == 2)
+		{
+			prob_estimates[0] = pairwise_prob[0][1];
+			prob_estimates[1] = pairwise_prob[1][0];
+		}
+		else
+			multiclass_probability(nr_class,pairwise_prob,prob_estimates);
 
 		int prob_max_idx = 0;
 		for(i=1;i<nr_class;i++)