ddR (version 0.1.1)

dlapply: Distributed version of 'lapply'. Similar to dmapply, but permits only one iterable argument, and output.type is always 'dlist'.

Description

Distributed version of 'lapply'. Similar to dmapply, but permits only one iterable argument, and output.type is always 'dlist'.

Usage

dlapply(X, FUN, ..., nparts = NULL)

Arguments

X

vector, matrix, list, data.frame, dlist, darray, or dframe or other iterable object to supply to the function in FUN.

FUN

the function to be applied to each element of 'X'.

...

optional arguments to 'FUN'.

nparts

number of partitions in the output dlist.

Value

• a dlist with number of partitions specified in 'nparts'

References

Prasad, S., Fard, A., Gupta, V., Martinez, J., LeFevre, J., Xu, V., Hsu, M., Roy, I. Large scale predictive analytics in Vertica: Fast data transfer, distributed model creation and in-database prediction. _Sigmod 2015_, 1657-1668.

Venkataraman, S., Bodzsar, E., Roy, I., AuYoung, A., and Schreiber, R. (2013) Presto: Distributed Machine Learning and Graph Processing with Sparse Matrices. _EuroSys 2013_, 197-210.

Homepage: https://github.com/vertica/ddR

Examples

a <- dlapply(1:5,function(x) x, nparts=3)
# A DList with 3 partitions,
# which in the aggregate contains the elements 1 through 5.
b <- dlapply(a,function(x) x+3) # AddR 3 to each element of dlist a.