[Rd] Intel Fortran compiler returns a -1 TRUE value

[Duncan Murdoch]

On 30/09/2014, 7:41 AM, Barry Rowlingson wrote:
> I have access to a cluster on which I have been supplied with R 3.1.0 which
> appears to have been built using the intel compiler tools.
> 
> The following minimal Fortran file:
> 
>       subroutine truth(lind)
>       logical lind
>       lind = .TRUE.
>       end
> 
> Compiles thusly:
> 
> arcadia> R CMD SHLIB truth.f
> ifort   -fpic  -O3 -xHOST -axCORE-AVX-I -fp-model precise  -c truth.f -o
> truth.o
> ifort: command line warning #10212: -fp-model precise evaluates in source
> precision with Fortran.
> icc -std=gnu99 -shared -L/usr/local/lib64 -o truth.so truth.o -lifport
> -lifcore -limf -lsvml -lm -lipgo -lirc -lpthread -lirc_s -ldl
> 
> 
> And runs so:
> 
>  > dyn.load("truth.so")
>  > z = .Fortran("truth",as.logical(TRUE))
>  > z[[1]]
>  [1] TRUE
>  > as.numeric(z[[1]])
>  [1] -1
>  > z[[1]] == TRUE
>  [1] FALSE
>  > all(z[[1]])
>  [1] TRUE
>  > identical(z[[1]],TRUE)
>  [1] FALSE
> 
> The value generated by Fortran's .TRUE. evaluates as "truthy" -- as in
> all(z[[1]]) -- but is neither equal to nor identical to TRUE. Its numeric
> conversion to -1 is most unusual, every other system I've tried converts to
> +1.
> 
> So.... wrong compiler flag on build? User error - never try comparing
> truthy values, as with the various flavours of NA? Or something else?
> 
> If its a compiler/config problem I'll pass it on to the cluster admin -
> I've had a good look for stuff on building R on Intel compilers, nothing
> stood out. I might try building R myself this afternoon but as I implied I
> don't have admin on this cluster so I might have to track down a bunch of
> library sources to build R from source.
> 
> If its a user error then I'll track down every instance of "if(foo==TRUE)"
> and shoot it, and it would be nice to have a note in ?TRUE
> 
> Some useful info:
> 
>> sessionInfo()
> R version 3.1.0 (2014-04-10)
> Platform: x86_64-unknown-linux-gnu (64-bit)
> 
> arcadia> ifort -v
> ifort version 13.0.0

This appears to be user error.  According to Writing R Extensions, the
Fortran type corresponding to R logical is INTEGER, not LOGICAL.

Duncan Murdoch