Dear All,
In R 3.4.2 (Linux), the compiler seems to have regressed:
$ R --vanilla
g = function() {
N = 1e7; ans = numeric(N)
system.time({for (j in 1:N) ans[j] = 1})
}
g()
# user system elapsed
# 4.272 0.000 4.272
g1 = compiler::cmpfun(g)
g1()
# user system elapsed
# 4.232 0.004 4.235
Running the above code in Windows 3.3.1, g() takes the same time, but g1()
takes around 0.5 seconds.
Removing the function wrapper we have
N = 1e7; ans = numeric(N)
system.time({for (j in 1:N) ans[j] = 1})
# user system elapsed
# 0.304 0.000 0.304
compiler::enableJIT(0)
#[1] 3
N = 1e7; ans = numeric(N)
system.time({for (j in 1:N) ans[j] = 1})
# user system elapsed
# 5.448 0.000 5.446
Best wishes
Colin
------------------
> sessionInfo()
R version 3.4.2 (2017-09-28)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 16.04.3 LTS
Matrix products: default
BLAS: /usr/lib/atlas-base/atlas/libblas.so.3.0
LAPACK: /usr/lib/atlas-base/atlas/liblapack.so.3.0
locale:
[1] LC_CTYPE=en_GB.UTF-8 LC_NUMERIC=C
[3] LC_TIME=en_GB.UTF-8 LC_COLLATE=en_GB.UTF-8
[5] LC_MONETARY=en_GB.UTF-8 LC_MESSAGES=en_GB.UTF-8
[7] LC_PAPER=en_GB.UTF-8 LC_NAME=C
[9] LC_ADDRESS=C LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_GB.UTF-8 LC_IDENTIFICATION=C
attached base packages:
[1] stats graphics grDevices utils datasets methods base
loaded via a namespace (and not attached):
[1] compiler_3.4.2
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