Oops, I got bitSlice wrong, hence and and or won't be right. bitSlice should be:
bitSlice <- function(x, from, length) shiftR(x, from) %% 2^length Bill Dunlap TIBCO Software wdunlap tibco.com On Thu, Jun 5, 2014 at 3:31 PM, William Dunlap <[email protected]> wrote: >> Double allows me to >> store large numbers but I can not perform bitwise shifting. > > It is a nuisance that bitwShiftL and bitwShitR don't just shift (and > wrap around to negative) for integers so you could use all 32 bits. > You could use doubles and multiply (*) and divide (%/%) by 2^n instead > of shifting left and right by n bits. That would give you 52 bits. > Bitwise 'and' and 'or' with doubles is harder to do efficiently at the > R level but you can get it done with the following: > > shiftL <- function(x, n) x * 2^n > shiftR <- function(x, n) x %/% 2^n > or <- function(x, y) .bitOp(x, y, bitwOr) > and <- function(x, y) .bitOp(x, y, bitwAnd) > bitSlice <- function(x, from, length) shiftR(x, from) %% 2^(from+length) > .bitOp <- function(x, y, bitwOp) bitwOp(bitSlice(x, 0, 26),bitSlice(y, > 0, 26)) + shiftL(bitwOp(bitSlice(x, 26, 26), bitSlice(y, 26, 26)), 26) > Bill Dunlap > TIBCO Software > wdunlap tibco.com > > > On Thu, Jun 5, 2014 at 11:43 AM, Koustubh Bagade <[email protected]> > wrote: >> Hi >> >> I am working on numbers between 0 - 2^32. I want to perform bit-wise shift >> operations on these numbers. Integer allows me to do bitwise shift >> operations but number range is limited to 0 - 2^31. Double allows me to >> store large numbers but I can not perform bitwise shifting. >> >> I can not change programming language as it is part of larger project. >> >> Is there a way to solve this problem? Perhaps using data types similar to >> unsigned integer or long integer? >> >> Thanks >> >> Koustubh Bagade >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> [email protected] mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
