ld_resample.c

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#include <gsl/gsl_rng.h>
#include <gsl/gsl_randist.h>
#include <gsl/gsl_math.h>

#include <math.h>
#include <options/options.h>


#include "../csm/csm_all.h"

struct {
        double interval;
        int seed;
}p ;

LDP ld_resample(LDP ld);

gsl_rng * rng;

int main(int argc, const char ** argv) {
        sm_set_program_name(argv[0]);
        
        
        struct option* ops = options_allocate(3);
        options_double(ops, "interval", &p.interval, sqrt(2.0), " 1 = no resampling");
                
        if(!options_parse_args(ops, argc, argv)) {
                options_print_help(ops, stderr);
                return -1;
        }

        int count = -1;
        LDP ld;
        while( (ld = ld_read_smart(stdin))) {
                count++;
                
                if(!ld_valid_fields(ld))  {
                        sm_error("Invalid laser data (#%d in file)\n", count);
                        continue;
                }
                
/*              if(count & 1) {*/
                        LDP ld2 = ld_resample(ld);
                        ld_write_as_json(ld2, stdout);
                        ld_free(ld2);
                        ld_free(ld);
/*              } else {
                        ld_write_as_json(ld, stdout);
                        ld_free(ld);
                }*/

                count++;
        }
        
        return 0;
}

LDP ld_resample(LDP ld) {
        /* FIXME magic number */
        int n = (int) (floor(ld->nrays / p.interval));
        
        LDP ld2 = ld_alloc_new(n);      
        int k;
        for(k=0;k<n;k++) {
                double index = k * p.interval;
                int i = (int) floor(index);
                int j = i + 1;
                double a = 1 - (index - i);
        
                
                if(  (j>= ld->nrays) || !ld->valid[i] || !ld->valid[j]) {
                        ld2->valid[k] = 0;
                        ld2->readings[k] = NAN;
                        ld2->alpha_valid[k] = 0;
                        ld2->alpha[k] = NAN;
                        ld2->theta[k] = ld->theta[i];
                } else {
                        ld2->theta[k] = a * ld->theta[i] + (1-a) * ld->theta[j];
                        
        
                        if(is_nan(ld2->theta[k])) {
                                sm_debug("Hey, k=%d theta[%d]=%f theta[%d]=%f\n",
                                        k,i,ld->theta[i],j,ld->theta[j]);
                        }

                        ld2->readings[k] = a * ld->readings[i] + (1-a) * ld->readings[j];
                        ld2->valid[k] = 1;
                }
                
/*              sm_debug("k=%d index=%f i=%d a=%f valid %d reading %f\n", k,index,i,a,ld2->valid[k],ld2->readings[k]);*/
        }
        
        ld2->min_theta = ld2->theta[0];
        ld2->max_theta = ld2->theta[n-1];
        ld2->tv = ld->tv;

        copy_d(ld->odometry, 3, ld2->odometry);
        copy_d(ld->estimate, 3, ld2->estimate);
        
        
        return ld2;
}