svm_scale.java

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

class svm_scale
{
        private String line = null;
        private double lower = -1.0;
        private double upper = 1.0;
        private double y_lower;
        private double y_upper;
        private boolean y_scaling = false;
        private double[] feature_max;
        private double[] feature_min;
        private double y_max = -Double.MAX_VALUE;
        private double y_min = Double.MAX_VALUE;
        private int max_index;
        private long num_nonzeros = 0;
        private long new_num_nonzeros = 0;

        private static void exit_with_help()
        {
                System.out.print(
                 "Usage: svm-scale [options] data_filename\n"
                +"options:\n"
                +"-l lower : x scaling lower limit (default -1)\n"
                +"-u upper : x scaling upper limit (default +1)\n"
                +"-y y_lower y_upper : y scaling limits (default: no y scaling)\n"
                +"-s save_filename : save scaling parameters to save_filename\n"
                +"-r restore_filename : restore scaling parameters from restore_filename\n"
                );
                System.exit(1);
        }

        private BufferedReader rewind(BufferedReader fp, String filename) throws IOException
        {
                fp.close();
                return new BufferedReader(new FileReader(filename));
        }

        private void output_target(double value)
        {
                if(y_scaling)
                {
                        if(value == y_min)
                                value = y_lower;
                        else if(value == y_max)
                                value = y_upper;
                        else
                                value = y_lower + (y_upper-y_lower) *
                                (value-y_min) / (y_max-y_min);
                }

                System.out.print(value + " ");
        }

        private void output(int index, double value)
        {
                /* skip single-valued attribute */
                if(feature_max[index] == feature_min[index])
                        return;

                if(value == feature_min[index])
                        value = lower;
                else if(value == feature_max[index])
                        value = upper;
                else
                        value = lower + (upper-lower) * 
                                (value-feature_min[index])/
                                (feature_max[index]-feature_min[index]);

                if(value != 0)
                {
                        System.out.print(index + ":" + value + " ");
                        new_num_nonzeros++;
                }
        }

        private String readline(BufferedReader fp) throws IOException
        {
                line = fp.readLine();
                return line;
        }

        private void run(String []argv) throws IOException
        {
                int i,index;
                BufferedReader fp = null, fp_restore = null;
                String save_filename = null;
                String restore_filename = null;
                String data_filename = null;


                for(i=0;i<argv.length;i++)
                {
                        if (argv[i].charAt(0) != '-')   break;
                        ++i;
                        switch(argv[i-1].charAt(1))
                        {
                                case 'l': lower = Double.parseDouble(argv[i]);  break;
                                case 'u': upper = Double.parseDouble(argv[i]);  break;
                                case 'y':
                                          y_lower = Double.parseDouble(argv[i]);
                                          ++i;
                                          y_upper = Double.parseDouble(argv[i]);
                                          y_scaling = true;
                                          break;
                                case 's': save_filename = argv[i];      break;
                                case 'r': restore_filename = argv[i];   break;
                                default:
                                          System.err.println("unknown option");
                                          exit_with_help();
                        }
                }

                if(!(upper > lower) || (y_scaling && !(y_upper > y_lower)))
                {
                        System.err.println("inconsistent lower/upper specification");
                        System.exit(1);
                }
                if(restore_filename != null && save_filename != null)
                {
                        System.err.println("cannot use -r and -s simultaneously");
                        System.exit(1);
                }

                if(argv.length != i+1)
                        exit_with_help();

                data_filename = argv[i];
                try {
                        fp = new BufferedReader(new FileReader(data_filename));
                } catch (Exception e) {
                        System.err.println("can't open file " + data_filename);
                        System.exit(1);
                }

                /* assumption: min index of attributes is 1 */
                /* pass 1: find out max index of attributes */
                max_index = 0;

                if(restore_filename != null)
                {
                        int idx, c;

                        try {
                                fp_restore = new BufferedReader(new FileReader(restore_filename));
                        }
                        catch (Exception e) {
                                System.err.println("can't open file " + restore_filename);
                                System.exit(1);
                        }
                        if((c = fp_restore.read()) == 'y')
                        {
                                fp_restore.readLine();
                                fp_restore.readLine();          
                                fp_restore.readLine();          
                        }
                        fp_restore.readLine();
                        fp_restore.readLine();

                        String restore_line = null;
                        while((restore_line = fp_restore.readLine())!=null)
                        {
                                StringTokenizer st2 = new StringTokenizer(restore_line);
                                idx = Integer.parseInt(st2.nextToken());
                                max_index = Math.max(max_index, idx);
                        }
                        fp_restore = rewind(fp_restore, restore_filename);
                }

                while (readline(fp) != null)
                {
                        StringTokenizer st = new StringTokenizer(line," \t\n\r\f:");
                        st.nextToken();
                        while(st.hasMoreTokens())
                        {
                                index = Integer.parseInt(st.nextToken());
                                max_index = Math.max(max_index, index);
                                st.nextToken();
                                num_nonzeros++;
                        }
                }

                try {
                        feature_max = new double[(max_index+1)];
                        feature_min = new double[(max_index+1)];
                } catch(OutOfMemoryError e) {
                        System.err.println("can't allocate enough memory");
                        System.exit(1);
                }

                for(i=0;i<=max_index;i++)
                {
                        feature_max[i] = -Double.MAX_VALUE;
                        feature_min[i] = Double.MAX_VALUE;
                }

                fp = rewind(fp, data_filename);

                /* pass 2: find out min/max value */
                while(readline(fp) != null)
                {
                        int next_index = 1;
                        double target;
                        double value;

                        StringTokenizer st = new StringTokenizer(line," \t\n\r\f:");
                        target = Double.parseDouble(st.nextToken());
                        y_max = Math.max(y_max, target);
                        y_min = Math.min(y_min, target);

                        while (st.hasMoreTokens())
                        {
                                index = Integer.parseInt(st.nextToken());
                                value = Double.parseDouble(st.nextToken());

                                for (i = next_index; i<index; i++)
                                {
                                        feature_max[i] = Math.max(feature_max[i], 0);
                                        feature_min[i] = Math.min(feature_min[i], 0);
                                }

                                feature_max[index] = Math.max(feature_max[index], value);
                                feature_min[index] = Math.min(feature_min[index], value);
                                next_index = index + 1;
                        }

                        for(i=next_index;i<=max_index;i++)
                        {
                                feature_max[i] = Math.max(feature_max[i], 0);
                                feature_min[i] = Math.min(feature_min[i], 0);
                        }
                }

                fp = rewind(fp, data_filename);

                /* pass 2.5: save/restore feature_min/feature_max */
                if(restore_filename != null)
                {
                        // fp_restore rewinded in finding max_index 
                        int idx, c;
                        double fmin, fmax;

                        fp_restore.mark(2);                             // for reset
                        if((c = fp_restore.read()) == 'y')
                        {
                                fp_restore.readLine();          // pass the '\n' after 'y'
                                StringTokenizer st = new StringTokenizer(fp_restore.readLine());
                                y_lower = Double.parseDouble(st.nextToken());
                                y_upper = Double.parseDouble(st.nextToken());
                                st = new StringTokenizer(fp_restore.readLine());
                                y_min = Double.parseDouble(st.nextToken());
                                y_max = Double.parseDouble(st.nextToken());
                                y_scaling = true;
                        }
                        else
                                fp_restore.reset();

                        if(fp_restore.read() == 'x') {
                                fp_restore.readLine();          // pass the '\n' after 'x'
                                StringTokenizer st = new StringTokenizer(fp_restore.readLine());
                                lower = Double.parseDouble(st.nextToken());
                                upper = Double.parseDouble(st.nextToken());
                                String restore_line = null;
                                while((restore_line = fp_restore.readLine())!=null)
                                {
                                        StringTokenizer st2 = new StringTokenizer(restore_line);
                                        idx = Integer.parseInt(st2.nextToken());
                                        fmin = Double.parseDouble(st2.nextToken());
                                        fmax = Double.parseDouble(st2.nextToken());
                                        if (idx <= max_index)
                                        {
                                                feature_min[idx] = fmin;
                                                feature_max[idx] = fmax;
                                        }
                                }
                        }
                        fp_restore.close();
                }

                if(save_filename != null)
                {
                        Formatter formatter = new Formatter(new StringBuilder());
                        BufferedWriter fp_save = null;

                        try {
                                fp_save = new BufferedWriter(new FileWriter(save_filename));
                        } catch(IOException e) {
                                System.err.println("can't open file " + save_filename);
                                System.exit(1);
                        }

                        if(y_scaling)
                        {
                                formatter.format("y\n");
                                formatter.format("%.16g %.16g\n", y_lower, y_upper);
                                formatter.format("%.16g %.16g\n", y_min, y_max);
                        }
                        formatter.format("x\n");
                        formatter.format("%.16g %.16g\n", lower, upper);
                        for(i=1;i<=max_index;i++)
                        {
                                if(feature_min[i] != feature_max[i]) 
                                        formatter.format("%d %.16g %.16g\n", i, feature_min[i], feature_max[i]);
                        }
                        fp_save.write(formatter.toString());
                        fp_save.close();
                }

                /* pass 3: scale */
                while(readline(fp) != null)
                {
                        int next_index = 1;
                        double target;
                        double value;

                        StringTokenizer st = new StringTokenizer(line," \t\n\r\f:");
                        target = Double.parseDouble(st.nextToken());
                        output_target(target);
                        while(st.hasMoreElements())
                        {
                                index = Integer.parseInt(st.nextToken());
                                value = Double.parseDouble(st.nextToken());
                                for (i = next_index; i<index; i++)
                                        output(i, 0);
                                output(index, value);
                                next_index = index + 1;
                        }

                        for(i=next_index;i<= max_index;i++)
                                output(i, 0);
                        System.out.print("\n");
                }
                if (new_num_nonzeros > num_nonzeros)
                        System.err.print(
                         "Warning: original #nonzeros " + num_nonzeros+"\n"
                        +"         new      #nonzeros " + new_num_nonzeros+"\n"
                        +"Use -l 0 if many original feature values are zeros\n");

                fp.close();
        }

        public static void main(String argv[]) throws IOException
        {
                svm_scale s = new svm_scale();
                s.run(argv);
        }
}