Question

我有一个非常奇怪的DEoptim错误我已经＆＃34;修复了＃34;但是我不明白。

当我使用DEoptim包的parallel并行功能（即pType=1）时，我没有遇到任何问题。但是，当我使用foreach代替（我必须在可用的网格计算设置上使用）时，我遇到了问题。下面是我所拥有的问题的简化版本的MRE。 pType=1有效，pType=2指定foreachArgs时会返回错误：

目标函数结果与参数矩阵的长度不同

当我没有指定foreachArgs时，问题就会消失。有没有人对这个问题的根本原因有所了解？

library(zoo)
library(parallel)
library(doParallel)
library(DEoptim)


myfunc1 <- function(params){
    s <- myfunc2(params,ncal,n_left_cens,astats, X_ret, disc_length, X_acq, POP_0, POP_ann_growth)
    loss_func(s)
    }

myfunc2 = function(params,ncal,n_left_cens,astats, X_ret, disc_length, X_acq, POP_0, POP_ann_growth){
    sum(params) + ncal + n_left_cens + astats + X_ret + disc_length + X_acq + POP_0 + POP_ann_growth 
    }

loss_func = function(s){
    s
    }   


# General setup
ncal = 1
n_left_cens = 1
astats= 1
disc_length = 1
POP_0 = 1
POP_ann_growth = 1
X_acq = 1
X_ret = 1
params = c(1,1)
W = 1

paral = TRUE
itermax=100
ncores = detectCores()
cltype <- ifelse(.Platform$OS.type != "windows", "FORK", "PSOCK")
trace=TRUE

# bounds for search for DEoptim
lower = rep(-1,length(params))
upper = lower*-1




# parallel: works               
pType = 1
parVar = c("myfunc1","myfunc2","loss_func","W","ncal","n_left_cens","astats","X_ret","disc_length",
                        "X_acq","POP_0","POP_ann_growth")               
foreachArguments <- list("myfunc1","myfunc2","loss_func","ncal","n_left_cens","astats","X_ret","disc_length",
                        "X_acq","POP_0","POP_ann_growth")
clusters <- makeCluster(ncores, type = cltype)
registerDoParallel(clusters)
clusterExport(cl=clusters, varlist=foreachArguments, envir=environment())
results <- DEoptim(fn=myfunc1,lower=lower,upper=upper,
                DEoptim.control(itermax=itermax,trace=trace,parallelType=pType,
                parVar=parVar))
showConnections(all = TRUE)
closeAllConnections()





# foreach with foreachArgs specified: doesn't work
pType = 2               
clusters <- makeCluster(ncores, type = cltype)
registerDoParallel(clusters)
clusterExport(cl=clusters, varlist=foreachArguments, envir=environment())

results <- DEoptim(fn=myfunc1,lower=lower,upper=upper,
                DEoptim.control(itermax=itermax,trace=trace,parallelType=pType,
                foreachArgs=foreachArguments))
showConnections(all = TRUE)
closeAllConnections()





# foreach with foreachArgs unspecified: works
pType = 2               
foreachArguments <- list("myfunc1","myfunc2","loss_func","ncal","n_left_cens","astats","X_ret","disc_length",
                        "X_acq","POP_0","POP_ann_growth")
clusters <- makeCluster(ncores, type = cltype)
registerDoParallel(clusters)
clusterExport(cl=clusters, varlist=foreachArguments, envir=environment())

results <- DEoptim(fn=myfunc1,lower=lower,upper=upper,
                DEoptim.control(itermax=itermax,trace=trace,parallelType=pType))
showConnections(all = TRUE)
closeAllConnections()

Answer 1

来自?DEoptim.control：

foreachArgs：来自'foreach'函数的命名参数列表包''foreach'。参数'i'，'。combine'和'.export'是不可能在这里设置;它们是内部设定的。

您似乎与parVar的行为相混淆：

parVar：如果'parallelType = 1'则使用;变量名称列表（作为字符串）需要存在于环境中以供目标函数使用或被目标函数用作参数。

您需要将传递给foreach的参数指定为name = value对。例如：

foreachArguments <- list(.export = c("myfunc1", "myfunc2", "loss_func", "ncal",
 "n_left_cens", "astats", "X_ret", "disc_length", "X_acq","POP_0","POP_ann_growth")

我不确定是什么造成了这个特定的错误，但修复是“不要这样做。”＃34;＆＃34; ;）

以下是您如何实际使用foreachArgs参数的示例。请注意，我设置.verbose参数以使foreach打印诊断：

library(doParallel)
library(DEoptim)
clusters <- makeCluster(detectCores())
registerDoParallel(clusters)
obj_func <- function(params) { sum(params) }
results <- DEoptim(fn=obj_func, lower=c(-1, -1), upper=c(1, 1),
  DEoptim.control(parallelType=2, foreachArgs=list(.verbose=TRUE)))
stopCluster(clusters)

DEoptim错误：由于foreachArgs规范，目标函数结果的长度与参数矩阵的长度不同

1 个答案: