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| Libsvm is a simple, easy-to-use, and efficient software for SVM | |||||
| classification and regression. It solves C-SVM classification, nu-SVM | |||||
| classification, one-class-SVM, epsilon-SVM regression, and nu-SVM | |||||
| regression. It also provides an automatic model selection tool for | |||||
| C-SVM classification. This document explains the use of libsvm. | |||||
| Libsvm is available at | |||||
| http://www.csie.ntu.edu.tw/~cjlin/libsvm | |||||
| Please read the COPYRIGHT file before using libsvm. | |||||
| Table of Contents | |||||
| ================= | |||||
| - Quick Start | |||||
| - Installation and Data Format | |||||
| - `svm-train' Usage | |||||
| - `svm-predict' Usage | |||||
| - `svm-scale' Usage | |||||
| - Tips on Practical Use | |||||
| - Examples | |||||
| - Precomputed Kernels | |||||
| - Library Usage | |||||
| - Java Version | |||||
| - Building Windows Binaries | |||||
| - Additional Tools: Sub-sampling, Parameter Selection, Format checking, etc. | |||||
| - MATLAB/OCTAVE Interface | |||||
| - Python Interface | |||||
| - Additional Information | |||||
| Quick Start | |||||
| =========== | |||||
| If you are new to SVM and if the data is not large, please go to | |||||
| `tools' directory and use easy.py after installation. It does | |||||
| everything automatic -- from data scaling to parameter selection. | |||||
| Usage: easy.py training_file [testing_file] | |||||
| More information about parameter selection can be found in | |||||
| `tools/README.' | |||||
| Installation and Data Format | |||||
| ============================ | |||||
| On Unix systems, type `make' to build the `svm-train' and `svm-predict' | |||||
| programs. Run them without arguments to show the usages of them. | |||||
| On other systems, consult `Makefile' to build them (e.g., see | |||||
| 'Building Windows binaries' in this file) or use the pre-built | |||||
| binaries (Windows binaries are in the directory `windows'). | |||||
| The format of training and testing data file is: | |||||
| <label> <index1>:<value1> <index2>:<value2> ... | |||||
| . | |||||
| . | |||||
| . | |||||
| Each line contains an instance and is ended by a '\n' character. For | |||||
| classification, <label> is an integer indicating the class label | |||||
| (multi-class is supported). For regression, <label> is the target | |||||
| value which can be any real number. For one-class SVM, it's not used | |||||
| so can be any number. The pair <index>:<value> gives a feature | |||||
| (attribute) value: <index> is an integer starting from 1 and <value> | |||||
| is a real number. The only exception is the precomputed kernel, where | |||||
| <index> starts from 0; see the section of precomputed kernels. Indices | |||||
| must be in ASCENDING order. Labels in the testing file are only used | |||||
| to calculate accuracy or errors. If they are unknown, just fill the | |||||
| first column with any numbers. | |||||
| A sample classification data included in this package is | |||||
| `heart_scale'. To check if your data is in a correct form, use | |||||
| `tools/checkdata.py' (details in `tools/README'). | |||||
| Type `svm-train heart_scale', and the program will read the training | |||||
| data and output the model file `heart_scale.model'. If you have a test | |||||
| set called heart_scale.t, then type `svm-predict heart_scale.t | |||||
| heart_scale.model output' to see the prediction accuracy. The `output' | |||||
| file contains the predicted class labels. | |||||
| For classification, if training data are in only one class (i.e., all | |||||
| labels are the same), then `svm-train' issues a warning message: | |||||
| `Warning: training data in only one class. See README for details,' | |||||
| which means the training data is very unbalanced. The label in the | |||||
| training data is directly returned when testing. | |||||
| There are some other useful programs in this package. | |||||
| svm-scale: | |||||
| This is a tool for scaling input data file. | |||||
| svm-toy: | |||||
| This is a simple graphical interface which shows how SVM | |||||
| separate data in a plane. You can click in the window to | |||||
| draw data points. Use "change" button to choose class | |||||
| 1, 2 or 3 (i.e., up to three classes are supported), "load" | |||||
| button to load data from a file, "save" button to save data to | |||||
| a file, "run" button to obtain an SVM model, and "clear" | |||||
| button to clear the window. | |||||
| You can enter options in the bottom of the window, the syntax of | |||||
| options is the same as `svm-train'. | |||||
| Note that "load" and "save" consider dense data format both in | |||||
| classification and the regression cases. For classification, | |||||
| each data point has one label (the color) that must be 1, 2, | |||||
| or 3 and two attributes (x-axis and y-axis values) in | |||||
| [0,1). For regression, each data point has one target value | |||||
| (y-axis) and one attribute (x-axis values) in [0, 1). | |||||
| Type `make' in respective directories to build them. | |||||
| You need Qt library to build the Qt version. | |||||
| (available from http://www.trolltech.com) | |||||
| You need GTK+ library to build the GTK version. | |||||
| (available from http://www.gtk.org) | |||||
| The pre-built Windows binaries are in the `windows' | |||||
| directory. We use Visual C++ on a 64-bit machine. | |||||
| `svm-train' Usage | |||||
| ================= | |||||
| Usage: svm-train [options] training_set_file [model_file] | |||||
| options: | |||||
| -s svm_type : set type of SVM (default 0) | |||||
| 0 -- C-SVC (multi-class classification) | |||||
| 1 -- nu-SVC (multi-class classification) | |||||
| 2 -- one-class SVM | |||||
| 3 -- epsilon-SVR (regression) | |||||
| 4 -- nu-SVR (regression) | |||||
| -t kernel_type : set type of kernel 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_set_file) | |||||
| -d degree : set degree in kernel function (default 3) | |||||
| -g gamma : set gamma in kernel function (default 1/num_features) | |||||
| -r coef0 : set coef0 in kernel function (default 0) | |||||
| -c cost : set the parameter C of C-SVC, epsilon-SVR, and nu-SVR (default 1) | |||||
| -n nu : set the parameter nu of nu-SVC, one-class SVM, and nu-SVR (default 0.5) | |||||
| -p epsilon : set the epsilon in loss function of epsilon-SVR (default 0.1) | |||||
| -m cachesize : set cache memory size in MB (default 100) | |||||
| -e epsilon : set tolerance of termination criterion (default 0.001) | |||||
| -h shrinking : whether to use the shrinking heuristics, 0 or 1 (default 1) | |||||
| -b probability_estimates : whether to train a SVC or SVR model for probability estimates, 0 or 1 (default 0) | |||||
| -wi weight : set the parameter C of class i to weight*C, for C-SVC (default 1) | |||||
| -v n: n-fold cross validation mode | |||||
| -q : quiet mode (no outputs) | |||||
| The k in the -g option means the number of attributes in the input data. | |||||
| option -v randomly splits the data into n parts and calculates cross | |||||
| validation accuracy/mean squared error on them. | |||||
| See libsvm FAQ for the meaning of outputs. | |||||
| `svm-predict' Usage | |||||
| =================== | |||||
| Usage: svm-predict [options] test_file model_file output_file | |||||
| options: | |||||
| -b probability_estimates: whether to predict probability estimates, 0 or 1 (default 0); for one-class SVM only 0 is supported | |||||
| model_file is the model file generated by svm-train. | |||||
| test_file is the test data you want to predict. | |||||
| svm-predict will produce output in the output_file. | |||||
| `svm-scale' Usage | |||||
| ================= | |||||
| Usage: svm-scale [options] data_filename | |||||
| options: | |||||
| -l lower : x scaling lower limit (default -1) | |||||
| -u upper : x scaling upper limit (default +1) | |||||
| -y y_lower y_upper : y scaling limits (default: no y scaling) | |||||
| -s save_filename : save scaling parameters to save_filename | |||||
| -r restore_filename : restore scaling parameters from restore_filename | |||||
| See 'Examples' in this file for examples. | |||||
| Tips on Practical Use | |||||
| ===================== | |||||
| * Scale your data. For example, scale each attribute to [0,1] or [-1,+1]. | |||||
| * For C-SVC, consider using the model selection tool in the tools directory. | |||||
| * nu in nu-SVC/one-class-SVM/nu-SVR approximates the fraction of training | |||||
| errors and support vectors. | |||||
| * If data for classification are unbalanced (e.g. many positive and | |||||
| few negative), try different penalty parameters C by -wi (see | |||||
| examples below). | |||||
| * Specify larger cache size (i.e., larger -m) for huge problems. | |||||
| Examples | |||||
| ======== | |||||
| > svm-scale -l -1 -u 1 -s range train > train.scale | |||||
| > svm-scale -r range test > test.scale | |||||
| Scale each feature of the training data to be in [-1,1]. Scaling | |||||
| factors are stored in the file range and then used for scaling the | |||||
| test data. | |||||
| > svm-train -s 0 -c 5 -t 2 -g 0.5 -e 0.1 data_file | |||||
| Train a classifier with RBF kernel exp(-0.5|u-v|^2), C=10, and | |||||
| stopping tolerance 0.1. | |||||
| > svm-train -s 3 -p 0.1 -t 0 data_file | |||||
| Solve SVM regression with linear kernel u'v and epsilon=0.1 | |||||
| in the loss function. | |||||
| > svm-train -c 10 -w1 1 -w-2 5 -w4 2 data_file | |||||
| Train a classifier with penalty 10 = 1 * 10 for class 1, penalty 50 = | |||||
| 5 * 10 for class -2, and penalty 20 = 2 * 10 for class 4. | |||||
| > svm-train -s 0 -c 100 -g 0.1 -v 5 data_file | |||||
| Do five-fold cross validation for the classifier using | |||||
| the parameters C = 100 and gamma = 0.1 | |||||
| > svm-train -s 0 -b 1 data_file | |||||
| > svm-predict -b 1 test_file data_file.model output_file | |||||
| Obtain a model with probability information and predict test data with | |||||
| probability estimates | |||||
| Precomputed Kernels | |||||
| =================== | |||||
| Users may precompute kernel values and input them as training and | |||||
| testing files. Then libsvm does not need the original | |||||
| training/testing sets. | |||||
| Assume there are L training instances x1, ..., xL and. | |||||
| Let K(x, y) be the kernel | |||||
| value of two instances x and y. The input formats | |||||
| are: | |||||
| New training instance for xi: | |||||
| <label> 0:i 1:K(xi,x1) ... L:K(xi,xL) | |||||
| New testing instance for any x: | |||||
| <label> 0:? 1:K(x,x1) ... L:K(x,xL) | |||||
| That is, in the training file the first column must be the "ID" of | |||||
| xi. In testing, ? can be any value. | |||||
| All kernel values including ZEROs must be explicitly provided. Any | |||||
| permutation or random subsets of the training/testing files are also | |||||
| valid (see examples below). | |||||
| Note: the format is slightly different from the precomputed kernel | |||||
| package released in libsvmtools earlier. | |||||
| Examples: | |||||
| Assume the original training data has three four-feature | |||||
| instances and testing data has one instance: | |||||
| 15 1:1 2:1 3:1 4:1 | |||||
| 45 2:3 4:3 | |||||
| 25 3:1 | |||||
| 15 1:1 3:1 | |||||
| If the linear kernel is used, we have the following new | |||||
| training/testing sets: | |||||
| 15 0:1 1:4 2:6 3:1 | |||||
| 45 0:2 1:6 2:18 3:0 | |||||
| 25 0:3 1:1 2:0 3:1 | |||||
| 15 0:? 1:2 2:0 3:1 | |||||
| ? can be any value. | |||||
| Any subset of the above training file is also valid. For example, | |||||
| 25 0:3 1:1 2:0 3:1 | |||||
| 45 0:2 1:6 2:18 3:0 | |||||
| implies that the kernel matrix is | |||||
| [K(2,2) K(2,3)] = [18 0] | |||||
| [K(3,2) K(3,3)] = [0 1] | |||||
| Library Usage | |||||
| ============= | |||||
| These functions and structures are declared in the header file | |||||
| `svm.h'. You need to #include "svm.h" in your C/C++ source files and | |||||
| link your program with `svm.cpp'. You can see `svm-train.c' and | |||||
| `svm-predict.c' for examples showing how to use them. We define | |||||
| LIBSVM_VERSION and declare `extern int libsvm_version; ' in svm.h, so | |||||
| you can check the version number. | |||||
| Before you classify test data, you need to construct an SVM model | |||||
| (`svm_model') using training data. A model can also be saved in | |||||
| a file for later use. Once an SVM model is available, you can use it | |||||
| to classify new data. | |||||
| - Function: struct svm_model *svm_train(const struct svm_problem *prob, | |||||
| const struct svm_parameter *param); | |||||
| This function constructs and returns an SVM model according to | |||||
| the given training data and parameters. | |||||
| struct svm_problem describes the problem: | |||||
| struct svm_problem | |||||
| { | |||||
| int l; | |||||
| double *y; | |||||
| struct svm_node **x; | |||||
| }; | |||||
| where `l' is the number of training data, and `y' is an array containing | |||||
| their target values. (integers in classification, real numbers in | |||||
| regression) `x' is an array of pointers, each of which points to a sparse | |||||
| representation (array of svm_node) of one training vector. | |||||
| For example, if we have the following training data: | |||||
| LABEL ATTR1 ATTR2 ATTR3 ATTR4 ATTR5 | |||||
| ----- ----- ----- ----- ----- ----- | |||||
| 1 0 0.1 0.2 0 0 | |||||
| 2 0 0.1 0.3 -1.2 0 | |||||
| 1 0.4 0 0 0 0 | |||||
| 2 0 0.1 0 1.4 0.5 | |||||
| 3 -0.1 -0.2 0.1 1.1 0.1 | |||||
| then the components of svm_problem are: | |||||
| l = 5 | |||||
| y -> 1 2 1 2 3 | |||||
| x -> [ ] -> (2,0.1) (3,0.2) (-1,?) | |||||
| [ ] -> (2,0.1) (3,0.3) (4,-1.2) (-1,?) | |||||
| [ ] -> (1,0.4) (-1,?) | |||||
| [ ] -> (2,0.1) (4,1.4) (5,0.5) (-1,?) | |||||
| [ ] -> (1,-0.1) (2,-0.2) (3,0.1) (4,1.1) (5,0.1) (-1,?) | |||||
| where (index,value) is stored in the structure `svm_node': | |||||
| struct svm_node | |||||
| { | |||||
| int index; | |||||
| double value; | |||||
| }; | |||||
| index = -1 indicates the end of one vector. Note that indices must | |||||
| be in ASCENDING order. | |||||
| struct svm_parameter describes the parameters of an SVM model: | |||||
| struct svm_parameter | |||||
| { | |||||
| int svm_type; | |||||
| int kernel_type; | |||||
| int degree; /* for poly */ | |||||
| double gamma; /* for poly/rbf/sigmoid */ | |||||
| double coef0; /* for poly/sigmoid */ | |||||
| /* these are for training only */ | |||||
| double cache_size; /* in MB */ | |||||
| double eps; /* stopping criteria */ | |||||
| double C; /* for C_SVC, EPSILON_SVR, and NU_SVR */ | |||||
| int nr_weight; /* for C_SVC */ | |||||
| int *weight_label; /* for C_SVC */ | |||||
| double* weight; /* for C_SVC */ | |||||
| double nu; /* for NU_SVC, ONE_CLASS, and NU_SVR */ | |||||
| double p; /* for EPSILON_SVR */ | |||||
| int shrinking; /* use the shrinking heuristics */ | |||||
| int probability; /* do probability estimates */ | |||||
| }; | |||||
| svm_type can be one of C_SVC, NU_SVC, ONE_CLASS, EPSILON_SVR, NU_SVR. | |||||
| C_SVC: C-SVM classification | |||||
| NU_SVC: nu-SVM classification | |||||
| ONE_CLASS: one-class-SVM | |||||
| EPSILON_SVR: epsilon-SVM regression | |||||
| NU_SVR: nu-SVM regression | |||||
| kernel_type can be one of LINEAR, POLY, RBF, SIGMOID. | |||||
| LINEAR: u'*v | |||||
| POLY: (gamma*u'*v + coef0)^degree | |||||
| RBF: exp(-gamma*|u-v|^2) | |||||
| SIGMOID: tanh(gamma*u'*v + coef0) | |||||
| PRECOMPUTED: kernel values in training_set_file | |||||
| cache_size is the size of the kernel cache, specified in megabytes. | |||||
| C is the cost of constraints violation. | |||||
| eps is the stopping criterion. (we usually use 0.00001 in nu-SVC, | |||||
| 0.001 in others). nu is the parameter in nu-SVM, nu-SVR, and | |||||
| one-class-SVM. p is the epsilon in epsilon-insensitive loss function | |||||
| of epsilon-SVM regression. shrinking = 1 means shrinking is conducted; | |||||
| = 0 otherwise. probability = 1 means model with probability | |||||
| information is obtained; = 0 otherwise. | |||||
| nr_weight, weight_label, and weight are used to change the penalty | |||||
| for some classes (If the weight for a class is not changed, it is | |||||
| set to 1). This is useful for training classifier using unbalanced | |||||
| input data or with asymmetric misclassification cost. | |||||
| nr_weight is the number of elements in the array weight_label and | |||||
| weight. Each weight[i] corresponds to weight_label[i], meaning that | |||||
| the penalty of class weight_label[i] is scaled by a factor of weight[i]. | |||||
| If you do not want to change penalty for any of the classes, | |||||
| just set nr_weight to 0. | |||||
| *NOTE* Because svm_model contains pointers to svm_problem, you can | |||||
| not free the memory used by svm_problem if you are still using the | |||||
| svm_model produced by svm_train(). | |||||
| *NOTE* To avoid wrong parameters, svm_check_parameter() should be | |||||
| called before svm_train(). | |||||
| struct svm_model stores the model obtained from the training procedure. | |||||
| It is not recommended to directly access entries in this structure. | |||||
| Programmers should use the interface functions to get the values. | |||||
| struct svm_model | |||||
| { | |||||
| struct svm_parameter param; /* parameter */ | |||||
| int nr_class; /* number of classes, = 2 in regression/one class svm */ | |||||
| int l; /* total #SV */ | |||||
| struct svm_node **SV; /* SVs (SV[l]) */ | |||||
| double **sv_coef; /* coefficients for SVs in decision functions (sv_coef[k-1][l]) */ | |||||
| double *rho; /* constants in decision functions (rho[k*(k-1)/2]) */ | |||||
| double *probA; /* pairwise probability information */ | |||||
| double *probB; | |||||
| int *sv_indices; /* sv_indices[0,...,nSV-1] are values in [1,...,num_traning_data] to indicate SVs in the training set */ | |||||
| /* for classification only */ | |||||
| int *label; /* label of each class (label[k]) */ | |||||
| int *nSV; /* number of SVs for each class (nSV[k]) */ | |||||
| /* nSV[0] + nSV[1] + ... + nSV[k-1] = l */ | |||||
| /* XXX */ | |||||
| int free_sv; /* 1 if svm_model is created by svm_load_model*/ | |||||
| /* 0 if svm_model is created by svm_train */ | |||||
| }; | |||||
| param describes the parameters used to obtain the model. | |||||
| nr_class is the number of classes. It is 2 for regression and one-class SVM. | |||||
| l is the number of support vectors. SV and sv_coef are support | |||||
| vectors and the corresponding coefficients, respectively. Assume there are | |||||
| k classes. For data in class j, the corresponding sv_coef includes (k-1) y*alpha vectors, | |||||
| where alpha's are solutions of the following two class problems: | |||||
| 1 vs j, 2 vs j, ..., j-1 vs j, j vs j+1, j vs j+2, ..., j vs k | |||||
| and y=1 for the first j-1 vectors, while y=-1 for the remaining k-j | |||||
| vectors. For example, if there are 4 classes, sv_coef and SV are like: | |||||
| +-+-+-+--------------------+ | |||||
| |1|1|1| | | |||||
| |v|v|v| SVs from class 1 | | |||||
| |2|3|4| | | |||||
| +-+-+-+--------------------+ | |||||
| |1|2|2| | | |||||
| |v|v|v| SVs from class 2 | | |||||
| |2|3|4| | | |||||
| +-+-+-+--------------------+ | |||||
| |1|2|3| | | |||||
| |v|v|v| SVs from class 3 | | |||||
| |3|3|4| | | |||||
| +-+-+-+--------------------+ | |||||
| |1|2|3| | | |||||
| |v|v|v| SVs from class 4 | | |||||
| |4|4|4| | | |||||
| +-+-+-+--------------------+ | |||||
| See svm_train() for an example of assigning values to sv_coef. | |||||
| rho is the bias term (-b). probA and probB are parameters used in | |||||
| probability outputs. If there are k classes, there are k*(k-1)/2 | |||||
| binary problems as well as rho, probA, and probB values. They are | |||||
| aligned in the order of binary problems: | |||||
| 1 vs 2, 1 vs 3, ..., 1 vs k, 2 vs 3, ..., 2 vs k, ..., k-1 vs k. | |||||
| sv_indices[0,...,nSV-1] are values in [1,...,num_traning_data] to | |||||
| indicate support vectors in the training set. | |||||
| label contains labels in the training data. | |||||
| nSV is the number of support vectors in each class. | |||||
| free_sv is a flag used to determine whether the space of SV should | |||||
| be released in free_model_content(struct svm_model*) and | |||||
| free_and_destroy_model(struct svm_model**). If the model is | |||||
| generated by svm_train(), then SV points to data in svm_problem | |||||
| and should not be removed. For example, free_sv is 0 if svm_model | |||||
| is created by svm_train, but is 1 if created by svm_load_model. | |||||
| - Function: double svm_predict(const struct svm_model *model, | |||||
| const struct svm_node *x); | |||||
| This function does classification or regression on a test vector x | |||||
| given a model. | |||||
| For a classification model, the predicted class for x is returned. | |||||
| For a regression model, the function value of x calculated using | |||||
| the model is returned. For an one-class model, +1 or -1 is | |||||
| returned. | |||||
| - Function: void svm_cross_validation(const struct svm_problem *prob, | |||||
| const struct svm_parameter *param, int nr_fold, double *target); | |||||
| This function conducts cross validation. Data are separated to | |||||
| nr_fold folds. Under given parameters, sequentially each fold is | |||||
| validated using the model from training the remaining. Predicted | |||||
| labels (of all prob's instances) in the validation process are | |||||
| stored in the array called target. | |||||
| The format of svm_prob is same as that for svm_train(). | |||||
| - Function: int svm_get_svm_type(const struct svm_model *model); | |||||
| This function gives svm_type of the model. Possible values of | |||||
| svm_type are defined in svm.h. | |||||
| - Function: int svm_get_nr_class(const svm_model *model); | |||||
| For a classification model, this function gives the number of | |||||
| classes. For a regression or an one-class model, 2 is returned. | |||||
| - Function: void svm_get_labels(const svm_model *model, int* label) | |||||
| For a classification model, this function outputs the name of | |||||
| labels into an array called label. For regression and one-class | |||||
| models, label is unchanged. | |||||
| - Function: void svm_get_sv_indices(const struct svm_model *model, int *sv_indices) | |||||
| This function outputs indices of support vectors into an array called sv_indices. | |||||
| The size of sv_indices is the number of support vectors and can be obtained by calling svm_get_nr_sv. | |||||
| Each sv_indices[i] is in the range of [1, ..., num_traning_data]. | |||||
| - Function: int svm_get_nr_sv(const struct svm_model *model) | |||||
| This function gives the number of total support vector. | |||||
| - Function: double svm_get_svr_probability(const struct svm_model *model); | |||||
| For a regression model with probability information, this function | |||||
| outputs a value sigma > 0. For test data, we consider the | |||||
| probability model: target value = predicted value + z, z: Laplace | |||||
| distribution e^(-|z|/sigma)/(2sigma) | |||||
| If the model is not for svr or does not contain required | |||||
| information, 0 is returned. | |||||
| - Function: double svm_predict_values(const svm_model *model, | |||||
| const svm_node *x, double* dec_values) | |||||
| This function gives decision values on a test vector x given a | |||||
| model, and return the predicted label (classification) or | |||||
| the function value (regression). | |||||
| For a classification model with nr_class classes, this function | |||||
| gives nr_class*(nr_class-1)/2 decision values in the array | |||||
| dec_values, where nr_class can be obtained from the function | |||||
| svm_get_nr_class. The order is label[0] vs. label[1], ..., | |||||
| label[0] vs. label[nr_class-1], label[1] vs. label[2], ..., | |||||
| label[nr_class-2] vs. label[nr_class-1], where label can be | |||||
| obtained from the function svm_get_labels. The returned value is | |||||
| the predicted class for x. Note that when nr_class = 1, this | |||||
| function does not give any decision value. | |||||
| For a regression model, dec_values[0] and the returned value are | |||||
| both the function value of x calculated using the model. For a | |||||
| one-class model, dec_values[0] is the decision value of x, while | |||||
| the returned value is +1/-1. | |||||
| - Function: double svm_predict_probability(const struct svm_model *model, | |||||
| const struct svm_node *x, double* prob_estimates); | |||||
| This function does classification or regression on a test vector x | |||||
| given a model with probability information. | |||||
| For a classification model with probability information, this | |||||
| function gives nr_class probability estimates in the array | |||||
| prob_estimates. nr_class can be obtained from the function | |||||
| svm_get_nr_class. The class with the highest probability is | |||||
| returned. For regression/one-class SVM, the array prob_estimates | |||||
| is unchanged and the returned value is the same as that of | |||||
| svm_predict. | |||||
| - Function: const char *svm_check_parameter(const struct svm_problem *prob, | |||||
| const struct svm_parameter *param); | |||||
| This function checks whether the parameters are within the feasible | |||||
| range of the problem. This function should be called before calling | |||||
| svm_train() and svm_cross_validation(). It returns NULL if the | |||||
| parameters are feasible, otherwise an error message is returned. | |||||
| - Function: int svm_check_probability_model(const struct svm_model *model); | |||||
| This function checks whether the model contains required | |||||
| information to do probability estimates. If so, it returns | |||||
| +1. Otherwise, 0 is returned. This function should be called | |||||
| before calling svm_get_svr_probability and | |||||
| svm_predict_probability. | |||||
| - Function: int svm_save_model(const char *model_file_name, | |||||
| const struct svm_model *model); | |||||
| This function saves a model to a file; returns 0 on success, or -1 | |||||
| if an error occurs. | |||||
| - Function: struct svm_model *svm_load_model(const char *model_file_name); | |||||
| This function returns a pointer to the model read from the file, | |||||
| or a null pointer if the model could not be loaded. | |||||
| - Function: void svm_free_model_content(struct svm_model *model_ptr); | |||||
| This function frees the memory used by the entries in a model structure. | |||||
| - Function: void svm_free_and_destroy_model(struct svm_model **model_ptr_ptr); | |||||
| This function frees the memory used by a model and destroys the model | |||||
| structure. It is equivalent to svm_destroy_model, which | |||||
| is deprecated after version 3.0. | |||||
| - Function: void svm_destroy_param(struct svm_parameter *param); | |||||
| This function frees the memory used by a parameter set. | |||||
| - Function: void svm_set_print_string_function(void (*print_func)(const char *)); | |||||
| Users can specify their output format by a function. Use | |||||
| svm_set_print_string_function(NULL); | |||||
| for default printing to stdout. | |||||
| Java Version | |||||
| ============ | |||||
| The pre-compiled java class archive `libsvm.jar' and its source files are | |||||
| in the java directory. To run the programs, use | |||||
| java -classpath libsvm.jar svm_train <arguments> | |||||
| java -classpath libsvm.jar svm_predict <arguments> | |||||
| java -classpath libsvm.jar svm_toy | |||||
| java -classpath libsvm.jar svm_scale <arguments> | |||||
| Note that you need Java 1.5 (5.0) or above to run it. | |||||
| You may need to add Java runtime library (like classes.zip) to the classpath. | |||||
| You may need to increase maximum Java heap size. | |||||
| Library usages are similar to the C version. These functions are available: | |||||
| public class svm { | |||||
| public static final int LIBSVM_VERSION=322; | |||||
| public static svm_model svm_train(svm_problem prob, svm_parameter param); | |||||
| public static void svm_cross_validation(svm_problem prob, svm_parameter param, int nr_fold, double[] target); | |||||
| public static int svm_get_svm_type(svm_model model); | |||||
| public static int svm_get_nr_class(svm_model model); | |||||
| public static void svm_get_labels(svm_model model, int[] label); | |||||
| public static void svm_get_sv_indices(svm_model model, int[] indices); | |||||
| public static int svm_get_nr_sv(svm_model model); | |||||
| public static double svm_get_svr_probability(svm_model model); | |||||
| public static double svm_predict_values(svm_model model, svm_node[] x, double[] dec_values); | |||||
| public static double svm_predict(svm_model model, svm_node[] x); | |||||
| public static double svm_predict_probability(svm_model model, svm_node[] x, double[] prob_estimates); | |||||
| public static void svm_save_model(String model_file_name, svm_model model) throws IOException | |||||
| public static svm_model svm_load_model(String model_file_name) throws IOException | |||||
| public static String svm_check_parameter(svm_problem prob, svm_parameter param); | |||||
| public static int svm_check_probability_model(svm_model model); | |||||
| public static void svm_set_print_string_function(svm_print_interface print_func); | |||||
| } | |||||
| The library is in the "libsvm" package. | |||||
| Note that in Java version, svm_node[] is not ended with a node whose index = -1. | |||||
| Users can specify their output format by | |||||
| your_print_func = new svm_print_interface() | |||||
| { | |||||
| public void print(String s) | |||||
| { | |||||
| // your own format | |||||
| } | |||||
| }; | |||||
| svm.svm_set_print_string_function(your_print_func); | |||||
| Building Windows Binaries | |||||
| ========================= | |||||
| Windows binaries are available in the directory `windows'. To re-build | |||||
| them via Visual C++, use the following steps: | |||||
| 1. Open a DOS command box (or Visual Studio Command Prompt) and change | |||||
| to libsvm directory. If environment variables of VC++ have not been | |||||
| set, type | |||||
| ""C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\bin\amd64\vcvars64.bat"" | |||||
| You may have to modify the above command according which version of | |||||
| VC++ or where it is installed. | |||||
| 2. Type | |||||
| nmake -f Makefile.win clean all | |||||
| 3. (optional) To build shared library libsvm.dll, type | |||||
| nmake -f Makefile.win lib | |||||
| 4. (optional) To build 32-bit windows binaries, you must | |||||
| (1) Setup "C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\bin\vcvars32.bat" instead of vcvars64.bat | |||||
| (2) Change CFLAGS in Makefile.win: /D _WIN64 to /D _WIN32 | |||||
| Another way is to build them from Visual C++ environment. See details | |||||
| in libsvm FAQ. | |||||
| - Additional Tools: Sub-sampling, Parameter Selection, Format checking, etc. | |||||
| ============================================================================ | |||||
| See the README file in the tools directory. | |||||
| MATLAB/OCTAVE Interface | |||||
| ======================= | |||||
| Please check the file README in the directory `matlab'. | |||||
| Python Interface | |||||
| ================ | |||||
| See the README file in python directory. | |||||
| Additional Information | |||||
| ====================== | |||||
| If you find LIBSVM helpful, please cite it as | |||||
| Chih-Chung Chang and Chih-Jen Lin, LIBSVM : a library for support | |||||
| vector machines. ACM Transactions on Intelligent Systems and | |||||
| Technology, 2:27:1--27:27, 2011. Software available at | |||||
| http://www.csie.ntu.edu.tw/~cjlin/libsvm | |||||
| LIBSVM implementation document is available at | |||||
| http://www.csie.ntu.edu.tw/~cjlin/papers/libsvm.pdf | |||||
| For any questions and comments, please email cjlin@csie.ntu.edu.tw | |||||
| Acknowledgments: | |||||
| This work was supported in part by the National Science | |||||
| Council of Taiwan via the grant NSC 89-2213-E-002-013. | |||||
| The authors thank their group members and users | |||||
| for many helpful discussions and comments. They are listed in | |||||
| http://www.csie.ntu.edu.tw/~cjlin/libsvm/acknowledgements | |||||