svm_predict.java

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import libsvm.*;
import java.io.*;
import java.util.*;

class svm_predict {
        private static double atof(String s)
        {
                return Double.valueOf(s).doubleValue();
        }

        private static int atoi(String s)
        {
                return Integer.parseInt(s);
        }

        private static void predict(BufferedReader input, DataOutputStream output, svm_model model, int predict_probability) throws IOException
        {
                int correct = 0;
                int total = 0;
                double error = 0;
                double sumv = 0, sumy = 0, sumvv = 0, sumyy = 0, sumvy = 0;

                int svm_type=svm.svm_get_svm_type(model);
                int nr_class=svm.svm_get_nr_class(model);
                double[] prob_estimates=null;

                if(predict_probability == 1)
                {
                        if(svm_type == svm_parameter.EPSILON_SVR ||
                           svm_type == svm_parameter.NU_SVR)
                        {
                                System.out.print("Prob. model for test data: target value = predicted value + z,\nz: Laplace distribution e^(-|z|/sigma)/(2sigma),sigma="+svm.svm_get_svr_probability(model)+"\n");
                        }
                        else
                        {
                                int[] labels=new int[nr_class];
                                svm.svm_get_labels(model,labels);
                                prob_estimates = new double[nr_class];
                                output.writeBytes("labels");
                                for(int j=0;j<nr_class;j++)
                                        output.writeBytes(" "+labels[j]);
                                output.writeBytes("\n");
                        }
                }
                while(true)
                {
                        String line = input.readLine();
                        if(line == null) break;

                        StringTokenizer st = new StringTokenizer(line," \t\n\r\f:");

                        double target = atof(st.nextToken());
                        int m = st.countTokens()/2;
                        svm_node[] x = new svm_node[m];
                        for(int j=0;j<m;j++)
                        {
                                x[j] = new svm_node();
                                x[j].index = atoi(st.nextToken());
                                x[j].value = atof(st.nextToken());
                        }

                        double v;
                        if (predict_probability==1 && (svm_type==svm_parameter.C_SVC || svm_type==svm_parameter.NU_SVC))
                        {
                                v = svm.svm_predict_probability(model,x,prob_estimates);
                                output.writeBytes(v+" ");
                                for(int j=0;j<nr_class;j++)
                                        output.writeBytes(prob_estimates[j]+" ");
                                output.writeBytes("\n");
                        }
                        else
                        {
                                v = svm.svm_predict(model,x);
                                output.writeBytes(v+"\n");
                        }

                        if(v == target)
                                ++correct;
                        error += (v-target)*(v-target);
                        sumv += v;
                        sumy += target;
                        sumvv += v*v;
                        sumyy += target*target;
                        sumvy += v*target;
                        ++total;
                }
                if(svm_type == svm_parameter.EPSILON_SVR ||
                   svm_type == svm_parameter.NU_SVR)
                {
                        System.out.print("Mean squared error = "+error/total+" (regression)\n");
                        System.out.print("Squared correlation coefficient = "+
                                 ((total*sumvy-sumv*sumy)*(total*sumvy-sumv*sumy))/
                                 ((total*sumvv-sumv*sumv)*(total*sumyy-sumy*sumy))+
                                 " (regression)\n");
                }
                else
                        System.out.print("Accuracy = "+(double)correct/total*100+
                                 "% ("+correct+"/"+total+") (classification)\n");
        }

        private static void exit_with_help()
        {
                System.err.print("usage: svm_predict [options] test_file model_file output_file\n"
                +"options:\n"
                +"-b probability_estimates: whether to predict probability estimates, 0 or 1 (default 0); one-class SVM not supported yet\n");
                System.exit(1);
        }

        public static void main(String argv[]) throws IOException
        {
                int i, predict_probability=0;

                // parse options
                for(i=0;i<argv.length;i++)
                {
                        if(argv[i].charAt(0) != '-') break;
                        ++i;
                        switch(argv[i-1].charAt(1))
                        {
                                case 'b':
                                        predict_probability = atoi(argv[i]);
                                        break;
                                default:
                                        System.err.print("Unknown option: " + argv[i-1] + "\n");
                                        exit_with_help();
                        }
                }
                if(i>=argv.length-2)
                        exit_with_help();
                try 
                {
                        BufferedReader input = new BufferedReader(new FileReader(argv[i]));
                        DataOutputStream output = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(argv[i+2])));
                        svm_model model = svm.svm_load_model(argv[i+1]);
                        if(predict_probability == 1)
                        {
                                if(svm.svm_check_probability_model(model)==0)
                                {
                                        System.err.print("Model does not support probabiliy estimates\n");
                                        System.exit(1);
                                }
                        }
                        else
                        {
                                if(svm.svm_check_probability_model(model)!=0)
                                {
                                        System.out.print("Model supports probability estimates, but disabled in prediction.\n");
                                }
                        }
                        predict(input,output,model,predict_probability);
                        input.close();
                        output.close();
                } 
                catch(FileNotFoundException e) 
                {
                        exit_with_help();
                }
                catch(ArrayIndexOutOfBoundsException e) 
                {
                        exit_with_help();
                }
        }
}