得到我的 testlabel 和 trainlabel 后,我在 libsvm 上实现了 SVM,我得到了 97.4359% 的准确率。( c = 1 和 g = 0.00375)
model = svmtrain(TrainLabel, TrainVec, '-c 1 -g 0.00375');
[predict_label, accuracy, dec_values] = svmpredict(TestLabel, TestVec, model);
在我找到最好的c和g之后,
bestcv = 0;
for log2c = -1:3,
for log2g = -4:1,
cmd = ['-v 5 -c ', num2str(2^log2c), ' -g ', num2str(2^log2g)];
cv = svmtrain(TrainLabel,TrainVec, cmd);
if (cv >= bestcv),
bestcv = cv; bestc = 2^log2c; bestg = 2^log2g;
end
fprintf('%g %g %g (best c=%g, g=%g, rate=%g)\n', log2c, log2g, cv, bestc, bestg, bestcv);
end
end
c = 8 和 g = 0.125
我再次实现模型:
model = svmtrain(TrainLabel, TrainVec, '-c 8 -g 0.125');
[predict_label, accuracy, dec_values] = svmpredict(TestLabel, TestVec, model);
我的准确率为 82.0513%
准确率怎么可能降低?不应该增加吗?还是我犯了任何错误?