Add a parallel option

[trinker]

A parallel option that runs sentiment and sentiment_by on multiple cores

[trinker]

Dump everything out to temp rds and read back to the clusters...add a library arg

[trinker]

Initial attempts leads to error on Windows (parallel seems to be using an old version of R and throws an error with regard to Rcpp being the wrong version fixed this by using newer version of R on path but now an error related to sentimentr indicating still an old version???). Maybe need to remove all R from path??

if (!require("pacman")) install.packages("pacman")
pacman::p_load(sentimentr, parallel, textshape, dplyr)


chunk_size <- 1e5
dir.create('data')

dat <- combine_data() %>%
    {.[rep(seq_len(nrow(.)), 100),]} %>%
    sample_n(nrow(.)) %>%
    split_index({inds <- chunk_size * 1:round(nrow(.)/chunk_size, 0); inds[inds < nrow(.)]})

tic <- Sys.time()

cl <- makeCluster(mc <- getOption("cl.cores", detectCores() - 2))

clusterEvalQ(cl, {
    library(sentimentr)
    library(lexicon)
})


parLapply(cl, dat, function(x){

    gc()

    senti_dat <- sentimentr::get_sentences(x)
    senti_dat <- sentimentr::sentiment_by(senti_dat)

    outfile <- sprintf('data/file_%s.rds', sample(1:100000))
    saveRDS(senti_dat, outfile)

}) %>%
    invisible()

stopCluster(cl)

Sys.time() - tic

Results in:

Error in checkForRemoteErrors(val) : 
  6 nodes produced errors; first error: 'get_sentences' is not an exported object from 'namespace:sentimentr'

[trinker]

http://appliedpredictivemodeling.com/blog/2018/1/17/parallel-processing

Is either of the following a better way to run parallel code:

https://github.com/r-lib/callr
https://github.com/r-lib/processx

A OS independent solution is needed. Re investigate available solutions and reach out to the R community for current best practices.

[trinker]

Here's where I ask the R community: https://twitter.com/tylerrinker/status/1044364197797265408

• https://github.com/HenrikBengtsson/future recommended by Julia Silge
• https://github.com/DavisVaughan/furrr recommended by Garrett Mooney

[bkmgit]

Some other packages:

• https://cran.r-project.org/package=snow
• https://cran.r-project.org/package=pbdMPI
  Futures looks easiest to use, but MPI has a long history of support. A tutorial with some relevant further reading:
  https://towardsdatascience.com/getting-started-with-parallel-programming-in-r-d5f801d43745