[Rd] mclapply returns NULLs on MacOS when running GAM

[Simon Urbanek]

Sorry, the code works perfectly fine for me in R even for 1e6 observations (but I was testing with R 4.0.0). Are you using some kind of GUI?

Cheers,
Simon


> On 28/04/2020, at 8:11 PM, Shian Su <su.s using wehi.edu.au> wrote:
> 
> Dear R-devel,
> 
> I am experiencing issues with running GAM models using mclapply, it fails to return any values if the data input becomes large. For example here the code runs fine with a df of 100 rows, but fails at 1000.
> 
> library(mgcv)
> library(parallel)
> 
>> df <- data.frame(
> +     x = 1:100,
> +     y = 1:100
> + )
>> 
>> mclapply(1:2, function(i, df) {
> +         fit <- gam(y ~ s(x, bs = "cs"), data = df)
> +     },
> +     df = df,
> +     mc.cores = 2L
> + )
> [[1]]
> 
> Family: gaussian
> Link function: identity
> 
> Formula:
> y ~ s(x, bs = "cs")
> 
> Estimated degrees of freedom:
> 9  total = 10
> 
> GCV score: 0
> 
> [[2]]
> 
> Family: gaussian
> Link function: identity
> 
> Formula:
> y ~ s(x, bs = "cs")
> 
> Estimated degrees of freedom:
> 9  total = 10
> 
> GCV score: 0
> 
>> 
>> 
>> df <- data.frame(
> +     x = 1:1000,
> +     y = 1:1000
> + )
>> 
>> mclapply(1:2, function(i, df) {
> +         fit <- gam(y ~ s(x, bs = "cs"), data = df)
> +     },
> +     df = df,
> +     mc.cores = 2L
> + )
> [[1]]
> NULL
> 
> [[2]]
> NULL
> 
> There is no error message returned, and the code runs perfectly fine in lapply.
> 
> I am on a MacBook 15 (2016) running MacOS 10.14.6 (Mojave) and R version 3.6.2. This bug could not be reproduced on my Ubuntu 19.10 running R 3.6.1.
> 
> Kind regards,
> Shian Su
> ----
> Shian Su
> PhD Student, Ritchie Lab 6W, Epigenetics and Development
> Walter & Eliza Hall Institute of Medical Research
> 1G Royal Parade, Parkville VIC 3052, Australia
> 
> 
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