Bad results when testing libsvm in matlab
5 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
can someone help me to solve this? I want to test whether this classification is already good or not. So, I try with data testing=data training. it will give 100% (acc) if the classification is good.
data= [170 66 ;
160 50 ;
170 63 ;
173 61 ;
168 58 ;
184 88 ;
189 94 ;
185 88 ]
labels=[-1;-1;-1;-1;-1;1;1;1];
numInst = size(data,1);
numLabels = max(labels);
testVal = [1 2 3 4 5 6 7 8];
trainLabel = labels(testVal,:);
trainData = data(testVal,:);
testData=data(testVal,:);
testLabel=labels(testVal,:);
numTrain = 8; numTest =8
%# train one-against-all models
model = cell(numLabels,1);
for k=1:numLabels
model{k} = svmtrain(double(trainLabel==k), trainData, '-c 1 -t 2 -g 0.2 -b 1');
end
%# get probability estimates of test instances using each model
prob = zeros(numTest,numLabels);
for k=1:numLabels
[~,~,p] = svmpredict(double(testLabel==k), testData, model{k}, '-b 1');
prob(:,k) = p(:,model{k}.Label==1); %# probability of class==k
end
%# predict the class with the highest probability
[~,pred] = max(prob,[],2);
acc = sum(pred == testLabel) ./ numel(testLabel) %# accuracy
C = confusionmat(testLabel, pred) %# confusion matrix
and this is the results
optimization finished, #iter = 16
nu = 0.645259 obj = -2.799682,
rho = -0.437644 nSV = 8, nBSV = 1 Total nSV = 8
Accuracy = 100% (8/8) (classification)
acc =
0.3750
C =
0 5
0 3
I dont know why there's two accuracy, and its different. the first one is 100% and the second one is 0.375. is my code false? it should be 100% not 37.5%. Can u help me to correct this code??
0 commentaires
Réponses (1)
pang jianfei
le 23 Mar 2013
Modifié(e) : pang jianfei
le 23 Mar 2013
The Accuracy = 100% (8/8) (classification) is from the svm toolbox ,which is automatic when you use the funttion of svmpredict.It is CRR which assume the right labels given by double(testLabel==k) .Well,acc is the CRR that you calculated.
0 commentaires
Voir également
Catégories
En savoir plus sur Statistics and Machine Learning Toolbox dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!