[Rd] NaN behavior of cumsum

Tomas Kalibera tomas.kalibera at gmail.com
Tue Jan 24 10:32:53 CET 2017

Hi Lukas,

thanks for the report. I've changed cumsum so that it is now consistent 
with cumprod wrt to NA/NaN propagation.
Now NaN is not turned into NA unnecessarily.

Still please be aware that generally NaNs may become NAs in R (on some 
?NaN says

"Computations involving ‘NaN’ will return ‘NaN’ or perhaps ‘NA’:
which of those two is not guaranteed and may depend on the R
platform (since compilers may re-order computations)."


On 01/20/2017 02:52 PM, Lukas Stadler wrote:
> Hi!
> I noticed that cumsum behaves different than the other cumulative functions wrt. NaN values:
>> values <- c(1,2,NaN,1)
>> for ( f in c(cumsum, cumprod, cummin, cummax)) print(f(values))
> [1]  1  3 NA NA
> [1]   1   2 NaN NaN
> [1]   1   1 NaN NaN
> [1]   1   2 NaN NaN
> The reason is that cumsum (in cum.c:33) contains an explicit check for ISNAN.
> Is that intentional?
> IMHO, ISNA would be better (because it would make the behavior consistent with the other functions).
> - Lukas
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel

More information about the R-devel mailing list