datafu-pig/src/main/java/datafu/pig/stats/DoubleVAR.java [107:260]:
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                  t.set(0, null);
                  t.set(1, null);
                  t.set(2, 0L);
                }
                else {
                  t.set(0, d);
                  t.set(1, d*d);
                  t.set(2, 1L);
                }
                return t;
            } catch(NumberFormatException nfe) {
                nfe.printStackTrace();
                // invalid input,
                // treat this input as null
                try {
                    t.set(0, null);
                    t.set(1, null);
                    t.set(2, 0L);
                } catch (ExecException e) {
                    throw e;
                }
                return t;
            } catch (ExecException ee) {
                ee.printStackTrace();
                throw ee;
            } catch (Exception e) {
                e.printStackTrace();
                int errCode = 2106;
                String msg = "Error while computing variance in " + this.getClass().getSimpleName();
                throw new ExecException(msg, errCode, PigException.BUG, e);
            }
                
        }
    }

    static public class Intermediate extends EvalFunc<Tuple> {
        @Override
        public Tuple exec(Tuple input) throws IOException {
            try {
                DataBag b = (DataBag)input.get(0);
                return combine(b);
            } catch (ExecException ee) {
                throw ee;
            } catch (Exception e) {
                int errCode = 2106;
                String msg = "Error while computing variacne in " + this.getClass().getSimpleName();
                throw new ExecException(msg, errCode, PigException.BUG, e);
            
            }
        }
    }

    static public class Final extends EvalFunc<Double> {
        @Override
        public Double exec(Tuple input) throws IOException {
            try {
                DataBag b = (DataBag)input.get(0);
                Tuple combined = combine(b);

                Double sum = (Double)combined.get(0);
                Double sumSquare = (Double)combined.get(1);
                if(sum == null) {
                    return null;
                }
                Long count = (Long)combined.get(2);

                Double var = null;
                
                if (count > 0) {
                    Double avg = new Double(sum / count);
                    Double avgSquare = new Double(sumSquare / count);
                    var = avgSquare - avg*avg;
                }
                return var;
            } catch (ExecException ee) {
                throw ee;
            } catch (Exception e) {
                int errCode = 2106;
                String msg = "Error while computing variance in " + this.getClass().getSimpleName();
                throw new ExecException(msg, errCode, PigException.BUG, e);
            }
        }
    }

    static protected Tuple combine(DataBag values) throws ExecException{
        double sum = 0;
        double sumSquare = 0;
        long totalCount = 0;

        // combine is called from Intermediate and Final
        // In either case, Initial would have been called
        // before and would have sent in valid tuples
        // Hence we don't need to check if incoming bag
        // is empty

        Tuple output = mTupleFactory.newTuple(3);
        boolean sawNonNull = false;
        for (Iterator<Tuple> it = values.iterator(); it.hasNext();) {
            Tuple t = it.next();
            Double d = (Double)t.get(0);
            Double dSquare = (Double)t.get(1);
            Long count = (Long)t.get(2);
            
            // we count nulls in var as contributing 0
            // a departure from SQL for performance of
            // COUNT() which implemented by just inspecting
            // size of the bag
            if(d == null) {
                d = 0.0;
                dSquare = 0.0;
            } else {
                sawNonNull = true;
            }
            sum += d;
            sumSquare += dSquare;
            totalCount += count;
        }
        if(sawNonNull) {
            output.set(0, new Double(sum));
            output.set(1, new Double(sumSquare));
        } else {
            output.set(0, null);
            output.set(1, null);
        }
        output.set(2, Long.valueOf(totalCount));
        return output;
    }

    static protected long count(Tuple input) throws ExecException {
        DataBag values = (DataBag)input.get(0);
        long cnt = 0;
        Iterator<Tuple> it = values.iterator();
        while (it.hasNext()){
            Tuple t = (Tuple)it.next();
            if (t != null && t.size() > 0 && t.get(0) != null)
                cnt ++;
        }
                    
        return cnt;
    }

    static protected Double sum(Tuple input) throws ExecException, IOException {
        DataBag values = (DataBag)input.get(0);
       
        // if we were handed an empty bag, return NULL
        if(values.size() == 0) {
            return null;
        }

        double sum = 0;
        boolean sawNonNull = false;
        for (Iterator<Tuple> it = values.iterator(); it.hasNext();) {
            Tuple t = it.next();
            try{
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datafu-pig/src/main/java/datafu/pig/stats/FloatVAR.java [109:262]:
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                    t.set(0, null);
                    t.set(1, null);
                    t.set(2, 0L);
                }
                else {
                    t.set(0, d);
                    t.set(1, d*d);
                    t.set(2, 1L);
                }
                return t;
            } catch(NumberFormatException nfe) {
                nfe.printStackTrace();
                // invalid input,
                // treat this input as null
                try {
                    t.set(0, null);
                    t.set(1, null);
                    t.set(2, 0L);
                } catch (ExecException e) {
                    throw e;
                }
                return t;
            } catch (ExecException ee) {
                ee.printStackTrace();
                throw ee;
            } catch (Exception e) {
                e.printStackTrace();
                int errCode = 2106;
                String msg = "Error while computing variance in " + this.getClass().getSimpleName();
                throw new ExecException(msg, errCode, PigException.BUG, e);
            }
                
        }
    }

    static public class Intermediate extends EvalFunc<Tuple> {
        @Override
        public Tuple exec(Tuple input) throws IOException {
            try {
                DataBag b = (DataBag)input.get(0);
                return combine(b);
            } catch (ExecException ee) {
                throw ee;
            } catch (Exception e) {
                int errCode = 2106;
                String msg = "Error while computing variacne in " + this.getClass().getSimpleName();
                throw new ExecException(msg, errCode, PigException.BUG, e);
            
            }
        }
    }

    static public class Final extends EvalFunc<Double> {
        @Override
        public Double exec(Tuple input) throws IOException {
            try {
                DataBag b = (DataBag)input.get(0);
                Tuple combined = combine(b);

                Double sum = (Double)combined.get(0);
                Double sumSquare = (Double)combined.get(1);
                if(sum == null) {
                    return null;
                }
                Long count = (Long)combined.get(2);

                Double var = null;
                
                if (count > 0) {
                    Double avg = new Double(sum / count);
                    Double avgSquare = new Double(sumSquare / count);
                    var = avgSquare - avg*avg;
                }
                return var;
            } catch (ExecException ee) {
                throw ee;
            } catch (Exception e) {
                int errCode = 2106;
                String msg = "Error while computing variance in " + this.getClass().getSimpleName();
                throw new ExecException(msg, errCode, PigException.BUG, e);
            }
        }
    }

    static protected Tuple combine(DataBag values) throws ExecException{
        double sum = 0;
        double sumSquare = 0;
        long totalCount = 0;

        // combine is called from Intermediate and Final
        // In either case, Initial would have been called
        // before and would have sent in valid tuples
        // Hence we don't need to check if incoming bag
        // is empty

        Tuple output = mTupleFactory.newTuple(3);
        boolean sawNonNull = false;
        for (Iterator<Tuple> it = values.iterator(); it.hasNext();) {
            Tuple t = it.next();
            Double d = (Double)t.get(0);
            Double dSquare = (Double)t.get(1);
            Long count = (Long)t.get(2);
            
            // we count nulls in var as contributing 0
            // a departure from SQL for performance of
            // COUNT() which implemented by just inspecting
            // size of the bag
            if(d == null) {
                d = 0.0;
                dSquare = 0.0;
            } else {
                sawNonNull = true;
            }
            sum += d;
            sumSquare += dSquare;
            totalCount += count;
        }
        if(sawNonNull) {
            output.set(0, new Double(sum));
            output.set(1, new Double(sumSquare));
        } else {
            output.set(0, null);
            output.set(1, null);
        }
        output.set(2, Long.valueOf(totalCount));
        return output;
    }

    static protected long count(Tuple input) throws ExecException {
        DataBag values = (DataBag)input.get(0);
        long cnt = 0;
        Iterator<Tuple> it = values.iterator();
        while (it.hasNext()){
            Tuple t = (Tuple)it.next();
            if (t != null && t.size() > 0 && t.get(0) != null)
                cnt ++;
        }
                    
        return cnt;
    }

    static protected Double sum(Tuple input) throws ExecException, IOException {
        DataBag values = (DataBag)input.get(0);
        
        // if we were handed an empty bag, return NULL
        if(values.size() == 0) {
            return null;
        }

        double sum = 0;
        boolean sawNonNull = false;
        for (Iterator<Tuple> it = values.iterator(); it.hasNext();) {
            Tuple t = it.next();
            try{
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