I wonder what is the history of "seq" and "seq.int"? >From "help(seq)", one reads that "'seq.int' is an internal generic which can be much faster but has a few restrictions". And indeed, "seq.int(1,99,by=2)" is over 40 times faster than "seq(1,99,by=2)" in a quick test I just did. This is not surprising given that "seq" is written in R whereas "seq.int" is a primitive written in C. The only documented restriction on "seq.int" that I can see is that it won't produce complex-valued sequences.
It would be nice if the 40-times-faster version could replace the slow version, if it can be made to do the same thing. But is there some reason I don't see that this makes this hard? Was the C version the original, and then someone decided that complex number support was essential, and most easily obtained by translating it to R? (The R code and C code are very parallel, so there was certainly a translation rather a rewrite one way or the other.) Or was the original in R, and someone rewrote it in C for speed, but stopped just short of being able to replace the R version with the C version because they didn't implement complex-valued sequences? Or is there some other feature that's missing from seq.int? By the way, I've submitted a bug report for seq.int, about it evaluating all it's arguments twice, but that isn't really related to the efficiency issue of seq versus seq.int. It is perhaps related to some strange code (and comments) in seq.int regarding special treatment for the along.with argument, which maybe also has some unusual history that isn't obvious... ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
