SVM学习笔记（2 ）libsvm--svmtrain\svmpredict函数说明
svmtrain(… );
%通过训练集来训练模型
svmpredict( … );
%对测试集进行预测
>>model = svmtrain(train_label,train_matrix, ['libsvm_options']);
-train_label:
An m by 1 vector of training labels (type must be double).
-train_matrix:
An m by n matrix of m training instances with n features.
It can be dense or sparse (type must be double).
-libsvm_options:
A string of training options in the same format as that ofLIBSVM.
===============
The 'svmtrain' functionreturns a model which can be used for future prediction.
>> [predicted_label,accuracy, decision_values/prob_estimates] = svmpredict(test_label, test_matrix,model, ['libsvm_options']);
-test_label:
An m by 1 vector of prediction labels. If labels of test dataare unknown, simply use any random values. (type must be double)
-testmatrix:
An m by n matrix of m testing instances with n features. It can be dense or sparse. (type must be double)
-model:
The output of svmtrain.
-libsvm_options:
A string of testing options in the same format as that ofLIBSVM.
===============
English:
libsvm_options:
-s svm_type : set type of SVM(default 0)
0 -- C-SVC
1 -- nu-SVC
2 -- one-class SVM
3 -- epsilon-SVR
4 -- nu-SVR
-t kernel_type : set type ofkernel function (default 2)
0 -- linear: u'*v
1 -- polynomial: (gamma*u'*v + coef0)^degree
2 -- radial basis function: exp(-gamma*|u-v|^2)
3 -- sigmoid: tanh(gamma*u'*v + coef0)
4 -- precomputed kernel (kernel values in training_instance_matrix)
-d degree : set degree inkernel function (default 3)
-g gamma : set gamma in kernelfunction (default 1/k)
-r coef0 : set coef0 in kernelfunction (default 0)
-c cost : set the parameter Cof C-SVC, epsilon-SVR, and nu-SVR (default 1)
-n nu : set the parameter nuof nu-SVC, one-class SVM, and nu-SVR (default 0.5)
-p epsilon : set the epsilonin loss function of epsilon-SVR (default 0.1)
-m cachesize : set cachememory size in MB (default 100)
-e epsilon : set tolerance oftermination criterion (default 0.001)
-h shrinking: whether to usethe shrinking heuristics, 0 or 1 (default 1)
-b probability_estimates:whether to train a SVC or SVR model for probability estimates, 0 or 1 (default0)
-wi weight: set the parameterC of class i to weight*C, for C-SVC (default 1)
-v n: n-fold cross validationmode
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Chinese:
Options：可用的选项即表示的涵义如下
-s svm类型：SVM设置类型(默认0)
0 -- C-SVC
1 --nu-SVC
2 – 一类SVM
3 -- e -SVR
4 -- nu-SVR
-t 核函数类型：核函数设置类型(默认2)
0 – 线性：u'v
1 – 多项式：(r*u'v + coef0)^degree
2 – RBF函数：exp(-r|u-v|^2)
3 –sigmoid：tanh(r*u'v + coef0)
-d degree：核函数中的degree设置(针对多项式核函数)(默认3)
-g r(gama)：核函数中的gamma函数设置(针对多项式/rbf/sigmoid核函数)(默认1/ k)
-r coef0：核函数中的coef0设置(针对多项式/sigmoid核函数)((默认0)
-c cost：设置C-SVC，e -SVR和v-SVR的参数(损失函数)(默认1)
-n nu：设置nu-SVC，一类SVM和nu- SVR的参数(默认0.5)
-p p：设置e -SVR 中损失函数p的值(默认0.1)
-m cachesize：设置cache内存大小，以MB为单位(默认40)
-e eps：设置允许的终止判据(默认0.001)
-h shrinking：是否使用启发式，0或1(默认1)
-wi weight：设置第几类的参数C为weight?C(C-SVC中的C)(默认1)
-v n: n-fold交互检验模式，n为fold的个数，必须大于等于2
其中-g选项中的k是指输入数据中的属性数。option -v 随机地将数据剖分为n部分并计算交互检验准确度和均方根误差。以上这些参数设置可以按照SVM的类型和核函数所支持的参数进行任意组合，如果设置的参数在函数或SVM类型中没有也不会产生影响，程序不会接受该参数；如果应有的参数设置不正确，参数将采用默认值。