m_Rprec_mult.c

/* 
   Copyright (c) 2008 - Chris Buckley. 

   Permission is granted for use and modification of this file for
   research, non-commercial purposes. 
*/

#include "common.h"
#include "sysfunc.h"
#include "trec_eval.h"
#include "functions.h"
#include "trec_format.h"

static int
te_calc_Rprec_mult(const EPI * epi, const REL_INFO * rel_info,
                   const RESULTS * results, const TREC_MEAS * tm,
                   TREC_EVAL * eval);
static double Rprec_cutoff_array[] = {
    0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0
};

static PARAMS default_Rprec_cutoffs = {
    NULL, sizeof(Rprec_cutoff_array) / sizeof(Rprec_cutoff_array[0]),
    &Rprec_cutoff_array[0]
};

/* See trec_eval.h for definition of TREC_MEAS */
TREC_MEAS te_meas_Rprec_mult = { "Rprec_mult",
    "    Precision measured at multiples of R (num_rel).\n\
    This is an attempt to measure topics at the same multiple milestones\n\
    in a retrieval (see explanation of R-prec), in order to determine\n\
    whether methods are precision oriented or recall oriented.  If method A\n\
    dominates method B at the low multiples but performs less well at the\n\
    high multiples then it is precision oriented (compared to B).\n\
    Default param: -m Rprec_mult.0.2,0.4,0.6,0.8,1.0,1.2,1.4,1.6,1.8,2.0 ...\n",
    te_init_meas_a_double_cut_double,
    te_calc_Rprec_mult,
    te_acc_meas_a_cut,
    te_calc_avg_meas_a_cut,
    te_print_single_meas_a_cut,
    te_print_final_meas_a_cut,
    (void *) &default_Rprec_cutoffs, -1
};

static int
te_calc_Rprec_mult(const EPI * epi, const REL_INFO * rel_info,
                   const RESULTS * results, const TREC_MEAS * tm,
                   TREC_EVAL * eval)
{
    double *cutoff_percents = (double *) tm->meas_params->param_values;
    long *cutoffs;              /* cutoffs expressed in num ret docs instead of percents */
    long current_cut;           /* current index into cutoffs */
    RES_RELS rr;
    long rel_so_far;
    long i;
    double precis, int_precis;

    if (UNDEF == te_form_res_rels(epi, rel_info, results, &rr))
        return (UNDEF);

    /* translate percentage of rels as given in the measure params, to
       an actual cutoff number of docs. */
    if (NULL == (cutoffs = Malloc(tm->meas_params->num_params, long)))
         return (UNDEF);
    for (i = 0; i < tm->meas_params->num_params; i++)
        cutoffs[i] = (long) (cutoff_percents[i] * rr.num_rel + 0.9);
    precis = (double) rr.num_rel_ret / (double) rr.num_ret;
    int_precis = precis;

    current_cut = tm->meas_params->num_params - 1;
    while (current_cut >= 0 && cutoffs[current_cut] > rr.num_ret) {
        eval->values[tm->eval_index + current_cut].value =
            (double) rr.num_rel_ret / (double) cutoffs[current_cut];
        current_cut--;
    }

    /* Loop over all retrieved docs in reverse order.  */
    rel_so_far = rr.num_rel_ret;
    for (i = rr.num_ret; i > 0 && rel_so_far > 0; i--) {
        precis = (double) rel_so_far / (double) i;
        if (int_precis < precis)
            int_precis = precis;
        while (current_cut >= 0 && i == cutoffs[current_cut]) {
            eval->values[tm->eval_index + current_cut].value = precis;
            current_cut--;
        }
        if (rr.results_rel_list[i - 1] >= epi->relevance_level) {
            rel_so_far--;
        }
    }

    (void) Free(cutoffs);

    return (1);
}