Example usage for org.apache.hadoop.io MapWritable values

Introduction

In this page you can find the example usage for org.apache.hadoop.io MapWritable values.

Prototype

@Override
    public Collection<Writable> values() 

Source Link

Usage

From source file:full_MapReduce.FindBestAttributeMapper.java

License:Open Source License

private double global_entropy(MapWritable data, int tot_tuple) {
    double res = 0.0;

    Map<Text, Integer> count_per_class = new HashMap<Text, Integer>();
    for (Writable tmp_cur_map : data.values()) {
        MapWritable cur_map = (MapWritable) tmp_cur_map;
        for (Writable cur_key : cur_map.keySet()) {
            Text cur_key_text = (Text) cur_key;
            if (!count_per_class.containsKey(cur_key_text)) {
                count_per_class.put(new Text(cur_key_text), 0);
            }//from w  w  w  . j  ava2 s  . c o  m

            count_per_class.put(cur_key_text,
                    ((IntWritable) cur_map.get(cur_key)).get() + count_per_class.get(cur_key_text));
        }
    }

    double p;
    for (Integer i : count_per_class.values()) {
        p = (i * 1.0) / tot_tuple;
        res -= p * Math.log(p) / Math.log(2);
    }

    return res;
}

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