我正在对开发中的包进行一些单元测试。其中一项测试失败了。具体来说,我有代码的并行版本和非并行版本。非并行版本完美运行。并行版本未通过单元测试,出现看似荒谬的错误。
## load my development package.
library(devtools) # for install_github
install_github("alexwhitworth/imputation")
## do some setup:
library(imputation)
library(kernlab)
library(parallel)
x1 <- matrix(rnorm(200), 20, 10)
x1[x1 > 1.25] <- NA
x3 <- create_canopies(x1, n_canopies= 5, q= 2)
prelim <- imputation:::impute_prelim(x3[[1]], parallel= TRUE, leave_cores= 1)
opt_h <- (4 * sd(x3[[1]][, -ncol(x3[[1]])], na.rm=T)^5 / (3 * nrow(x3[[1]])))^(1/5)
kern <- rbfdot(opt_h)
## write 2 identical functions:
## one in parallel
## one not in parallel
foo_parallel <- function(x_missing, x_complete, k, q, leave_cores) {
cl <- makeCluster(detectCores() - leave_cores)
x_missing_imputed <- parRapply(cl= cl, x_missing, function(i, x_complete) {
rowID = as.numeric(i[1])
i_original = unlist(i[-1])
x_comp_rowID <- which(as.integer(rownames(x_complete)) == rowID)
missing_cols <- which(is.na(x_complete[x_comp_rowID,]))
# calculate distances
distances <- imputation:::dist_q.matrix(x=rbind(x_complete[x_comp_rowID, ],
x_complete[-x_comp_rowID,]), ref= 1L, q= q)
return(distances)
}, x_complete= x_complete)
stopCluster(cl)
return(x_missing_imputed)
}
foo_nonparallel <- function(x_missing, x_complete, k, q) {
x_missing_imputed <- t(apply(x_missing, 1, function(i, x_complete) {
rowID = as.numeric(i[1])
i_original = unlist(i[-1])
x_comp_rowID <- which(as.integer(rownames(x_complete)) == rowID)
missing_cols <- which(is.na(x_complete[x_comp_rowID,]))
# calculate distances
distances <- imputation:::dist_q.matrix(x=rbind(x_complete[x_comp_rowID, ],
x_complete[-x_comp_rowID,]), ref= 1L, q= q)
return(distances)
}, x_complete= x_complete))
return(x_missing_imputed)
}
## test them
foo_parallel(prelim$x_missing, x3[[1]],k=3,q=2, leave_cores= 1) # fails
foo_nonparallel(prelim$x_missing, x3[[1]],k=3,q=2) # works
checkForRemoteErrors(val) 中的错误:2 个节点产生错误;第一个错误:ref 必须是 {1, nrow(x)} 中的整数。
如您所见,ref
明确定义为ref= 1L
1,nrow(x)。
library(parallel)
与导致此错误的交互发生了什么?
编辑- 我在 Windows 机器上:
R> sessionInfo()
R version 3.2.2 (2015-08-14)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 7 x64 (build 7601) Service Pack 1