LibsvmFileLoader.cpp

Go to the documentation of this file.

#include "LibsvmFileLoader.h"
#include "KernelMachines.h"

namespace damina
{

        LibsvmFileLoader::LibsvmFileLoader(string s) {
                this->filename = s;
        }
        
        LibsvmFileLoader::~LibsvmFileLoader() {
        }
        
        
        struct svm_problem *LibsvmFileLoader::load(bool precomputedKernel) {
                int elements, max_index, i, j;
                FILE *fp = fopen(this->filename.c_str(),"r");
                struct svm_problem *prob = (struct svm_problem *) malloc(sizeof(struct svm_problem));
                
                if (fp == NULL) {
                        fprintf(stderr, "can't open input file %s\n", this->filename.c_str());
                        fprintf(stderr, "reading from standard input...");
                        fp = stdin;
                        //return NULL;
                }
        
                prob->l = 0;
                elements = 0;
                while(1)
                {
                        int c = fgetc(fp);
                        switch(c)
                        {
                                case '\n':
                                        ++(prob->l);
                                        // fall through,
                                        // count the '-1' element
                                case ':':
                                        ++elements;
                                        break;
                                case EOF:
                                        goto out;
                                default:
                                        ;
                        }
                }
        out:
                rewind(fp);
        
                prob->y = (double *) malloc(sizeof(double) * prob->l);
                prob->x = (struct svm_node **) malloc(sizeof(struct svm_node*) * prob->l);
                struct svm_node *x_space = (struct svm_node *) malloc(sizeof(struct svm_node) * elements);
        
                max_index = 0;
                j=0;
                for(i=0;i<prob->l;i++)
                {
                        double label;
                        prob->x[i] = &x_space[j];
                        fscanf(fp,"%lf",&label);
                        prob->y[i] = label;
        
                        while(1)
                        {
                                int c;
                                do {
                                        c = getc(fp);
                                        if(c=='\n') goto out2;
                                } while(isspace(c));
                                ungetc(c,fp);
                                if (fscanf(fp,"%d:%lf",&(x_space[j].index),&(x_space[j].value)) < 2)
                                {
                                        fprintf(stderr,"Wrong input format at line %d\n", i+1);
                                        return NULL;
                                }
                                ++j;
                        }       
        out2:
                        if(j>=1 && x_space[j-1].index > max_index)
                                max_index = x_space[j-1].index;
                        x_space[j++].index = -1;
                }
                
                
        
//              if(param->gamma == 0)
//                      param->gamma = 1.0/max_index; //max_index is the number of attributes in the input data.
//      
                if (precomputedKernel) {
                        for (i = 0; i < prob->l; i++)
                        {
                                if (prob->x[i][0].index != 0)
                                {
                                        fprintf(stderr,"Wrong input format: first column must be 0:sample_serial_number\n");
                                        return NULL;
                                }
                                if ((int)prob->x[i][0].value <= 0 || (int)prob->x[i][0].value > max_index)
                                {
                                        fprintf(stderr,"Wrong input format: sample_serial_number out of range\n");
                                        return NULL;
                                }
                        }
                }
        
                fclose(fp);
                
                return prob;
        }

        struct svm_problem *LibsvmFileLoader::load(bool precomputedKernel, string s) {
                this->filename = s;
                return load(precomputedKernel);
        }
}

---