插入符号中列车的并行执行失败，未找到功能

昨天我更新了我的R包，从那以后并列执行列车功能失败了 .

似乎从工作者中调用的某些函数不可用 . 这些函数至少是flatTable和probFunction .

我在 生产环境 机器上遇到了这个问题，并且能够在干净的Windows 7 x64 VM上重现它 .

我在下面添加了一个最小的工作示例亲爱的stackoverflow用户：非常感谢！

# R 3.0.2 x64, RStudio Version 0.98.490, Windows 7 x64

data(iris)
library(caret) # 6.0-21
library(doParallel) # 1.0.6

model <- "rf"

# Fail
?probFunction
?flatTable

fitControl <- trainControl(
  method = "repeatedcv"
  , number = 5  ## 5-fold CV
  , repeats = 1   ## repeated one times
  , verboseIter =TRUE
)

#### Sequential Version ####

# Runs
train(Species ~ ., data = iris, method = model, trControl = fitControl)

#### Parallelized version ####

# Fails with 
# Error in e$fun(obj, substitute(ex), parent.frame(), e$data) : 
#  worker initialization failed: Error in eval(expr, envir, enclos): could not find function "flatTable"
cl <- makeCluster(3)
registerDoParallel(cl)

train(Species ~ ., data = iris, method = model, trControl = fitControl)

stopCluster(cl)

# Fails with 
# Error in { : task 1 failed - "could not find function "probFunction""
fitControl <- trainControl(
  method = "repeatedcv"
  , number = 5  ## 5-fold CV
  , repeats = 1   ## repeated one times
  , verboseIter =TRUE
  , classProbs = TRUE
)

cl <- makeCluster(3)
registerDoParallel(cl)

train(Species ~ ., data = iris, method = model, trControl = fitControl)

stopCluster(cl)

#### Again sequential version ####

# Fails with
# Error in summary.connection(connection) : invalid connection
train(Species ~ ., data = iris, method = model, trControl = fitControl)

R会话信息

R version 3.0.2 (2013-09-25)
Platform: x86_64-w64-mingw32/x64 (64-bit)

locale:
[1] LC_COLLATE=German_Germany.1252  LC_CTYPE=German_Germany.1252    LC_MONETARY=German_Germany.1252
[4] LC_NUMERIC=C                    LC_TIME=German_Germany.1252   

attached base packages:
[1] parallel  stats     graphics  grDevices utils     datasets  methods   base    

other attached packages:
[1] e1071_1.6-1        class_7.3-9        randomForest_4.6-7 doParallel_1.0.6   iterators_1.0.6  
[6] foreach_1.4.1      caret_6.0-21       ggplot2_0.9.3.1    lattice_0.20-23  

loaded via a namespace (and not attached):
[1] car_2.0-19         codetools_0.2-8    colorspace_1.2-4   compiler_3.0.2     dichromat_2.0-0  
 [6] digest_0.6.4       grid_3.0.2         gtable_0.1.2       labeling_0.2       MASS_7.3-29      
[11] munsell_0.4.2      nnet_7.3-7         plyr_1.8           proto_0.3-10       RColorBrewer_1.0-5
[16] reshape2_1.2.2     scales_0.2.3       stringr_0.6.2      tools_3.0.2