urn c
}

function get_xy_data_by_group(input, metric, rel_pairs) {
    var result = []
    var m = accessors[metric]
    for(i = 0; i < input.n_samples - 1; i++) {
        for(j=i+1; j < input.n_samples; j++){
            var c = getc(rel_pairs, input.samples[i], input.samples[j])
            if (result[c] == undefined) {
                result[c] = []
            }
            var v = m(input, i, j)
            if (v < 15) {
                v += (Math.random() - 0.5) / (7.0 * (v + 1))
            }
       