Reduce Algorithms

Reduce

Function objects available for the reduce and scan units include count, sum, mean etc. The function objects can be called for any key or value type. In Example–1, if it is desired to sum the numbers in one column and all their sixth roots in another, it can be done by adding reduce(sum(), 0.0, 0.0) to the dataflow. Check demoReduce for usage examples of these function objects.

ReduceAll

Algorithms available for the reduceAll unit include the following. Check demoReduceAll for usage examples of these function objects.

• summary: returns mean, stddev, min, max, median of a dataset.
• corr: correlates one column with all other columns.
• hist: bins the rows and calculates the frequency of each bin.