DistReduce(using,mapfun,args,reducefun)
DistReduce() is only run on sub-processes and is a way to shrink the
amount of data being passed to the accum.
Syntax
DistReduce(using,mapfun,args,reducefun)Description
DistReduce() is similar to DistApply() in that it
is run only on sub-processes. If there are a large number of segments per
sub-process, DistReduce() will shrink the amount of data being
passed to the accum and will perform better than DistApply(). If
there is a small number of segments per sub-process, DistApply()
may be faster than DistReduce().
Arguments
using- The column information for each segment. This "primes" the data for the sub-processes.
mapfun- The function to be applied to each segment.
args- The argument to
fun. reducefun- The function that reduces the amount of data being passed to the accum.
Currently,
reducefunruns only on sub-processes.
Return Value
A list of reduced results. The list length will equal the number of sub-processes.