libsvm savemodel and loadmodel

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savemodel 和 loadmodel的c代码如下：

#include "svm.h"#include "mex.h"#include "svm_model_matlab.h"static void fake_answer(mxArray *plhs[]){    plhs[0] = mxCreateDoubleMatrix(0, 0, mxREAL);}void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[]){    struct svm_model *model;    char *filename;    const char *error_msg;    int nr_feat;    // check input    if(nrhs != 2) {        mexPrintf("Usage: model = libsvmloadmodel('filename', num_of_feature);\n");        fake_answer(plhs);        return;    }    if(!mxIsChar(prhs[0]) || mxGetM(prhs[0])!=1) {        mexPrintf("filename should be given as string\n");        fake_answer(plhs);        return;    }    if(mxGetNumberOfElements(prhs[1])!=1) {        mexPrintf("number of features should be given as scalar\n");        fake_answer(plhs);        return;    }    // get filename and number of features    filename = mxArrayToString(prhs[0]);    nr_feat = (int) *(mxGetPr(prhs[1]));    // load model from file    model = svm_load_model(filename);    if (model == NULL) {        mexPrintf("Error occured while reading from file.\n");        fake_answer(plhs);        mxFree(filename);        return;    }    // convert MATLAB struct to C struct    error_msg = model_to_matlab_structure(plhs, nr_feat, model);    if(error_msg) {        mexPrintf("Error: can't convert libsvm model to matrix structure: %s\n", error_msg);        fake_answer(plhs);    }    // destroy model    svm_free_and_destroy_model(&model);    mxFree(filename);    return;}

savemode.c

#include "../svm.h"#include "mex.h"#include "svm_model_matlab.h"static void fake_answer(mxArray *plhs[]){    plhs[0] = mxCreateDoubleMatrix(0, 0, mxREAL);}void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[]){    struct svm_model *model;    char *filename;    const char *error_msg;    int status;    // check input    if(nrhs != 2) {        mexPrintf("Usage: svm_savemodel(model, 'filename');\n");        fake_answer(plhs);        return;    }    if(!mxIsStruct(prhs[0])) {        mexPrintf("model file should be a struct array\n");        fake_answer(plhs);        return;    }    if(!mxIsChar(prhs[1]) || mxGetM(prhs[1])!=1) {        mexPrintf("filename should be given as char(s)\n");        fake_answer(plhs);        return;    }    // convert MATLAB struct to C struct    model = matlab_matrix_to_model(prhs[0], &error_msg);    if(model == NULL) {        mexPrintf("Error: can't read model: %s\n", error_msg);        fake_answer(plhs);        return;    }    // get filename    filename = mxArrayToString(prhs[1]);    // save model to file    status = svm_save_model(filename,model);    if (status != 0) {        mexWarnMsgTxt("Error occured while writing to file.");    }    // destroy model    svm_free_and_destroy_model(&model);    mxFree(filename);    // return status value (0: success, -1: failure)    plhs[0] = mxCreateDoubleScalar(status);    return;}

之后在命令行下运行：

mex CFLAGS="\$CFLAGS -std=c99" -largeArrayDims loadmodel.c ../svm.cpp svm_model_matlab.cmex CFLAGS="\$CFLAGS -std=c99" -largeArrayDims savemodel.c ../svm.cpp svm_model_matlab.c

会得到savemodel 和loadmodel 两个函数

下面给出一个使用的例子：

%# load some data, train a model, save it to file[y,X] = libsvmread('./heart_scale');model = libsvmtrain(y, X, '-c 1 -g 0.07 -b 1');savemodel(model, 'm.model');%# load model from file, and use it to predict labelsm = loadmodel('m.model',size(X,2));[yy, acc, prob_est] = libsvmpredict(y, X, m, '-b 1');

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