/// <summary>Partitions the summation into parts and then return them as splits</summary>
public override IList <InputSplit> GetSplits(JobContext context)
{
//read sigma from conf
Configuration conf = context.GetConfiguration();
Summation sigma = SummationWritable.Read(typeof(DistSum), conf);
int nParts = conf.GetInt(NParts, 0);
//create splits
IList <InputSplit> splits = new AList <InputSplit>(nParts);
Summation[] parts = sigma.Partition(nParts);
for (int i = 0; i < parts.Length; ++i)
{
splits.AddItem(new DistSum.Machine.SummationSplit(parts[i]));
}
//LOG.info("parts[" + i + "] = " + parts[i]);
return(splits);
}
/// <summary>Partition sigma and execute the computations.</summary>
private Summation Execute(string name, Summation sigma)
{
Summation[] summations = sigma.Partition(parameters.nJobs);
IList <DistSum.Computation> computations = new AList <DistSum.Computation>();
for (int i = 0; i < summations.Length; i++)
{
computations.AddItem(new DistSum.Computation(this, i, name, summations[i]));
}
try
{
Org.Apache.Hadoop.Examples.PI.Util.Execute(parameters.nThreads, computations);
}
catch (Exception e)
{
throw new RuntimeException(e);
}
IList <Summation> combined = Org.Apache.Hadoop.Examples.PI.Util.Combine(Arrays.AsList
(summations));
return(combined.Count == 1 ? combined[0] : null);
}