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*To*: srfi-77@xxxxxxxxxxxxxxxxx*Subject*: [SRFI 77] integer-length and integer-sqrt*From*: Jens Axel Søgaard <jensaxel@xxxxxxxxxxxx>*Date*: Thu, 06 Oct 2005 17:54:23 +0200*Delivered-to*: srfi-77@xxxxxxxxxxxxxxxxx*In-reply-to*: <43454429.1090307@xxxxxxxxxxx>*References*: <43440EDA.1020900@xxxxxxxxxxx> <y9lfyrfw5bj.fsf@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> <43454429.1090307@xxxxxxxxxxx>*User-agent*: Mozilla Thunderbird 1.0.2 (Windows/20050317)

Thanks for a very interesting number srfi. Efficient (and portable) arithmetic in Scheme has been on my wish list for a long time. I propose adding the following two operations on integers. The first is INTEGER-LENGTH from CLHS <http://clhs.lisp.se/Body/f_intege.htm> which returns the number of bits needed to represent a given integer in binary two's-complement format. Although it is possible to define INTEGER-LENGTH as a library function, it will be more efficient as a primitive, since it can exploit the internal representation of an integer. The second is INTEGER-SQRT, which is discussed here: <http://groups.google.com/group/comp.lang.scheme/browse_frm/thread/dc06e91e306cf488/a9cf92f425bb3db1?lnk=st&q=lucier+integer-sqrt&rnum=1&hl=en#a9cf92f425bb3db1> I consider INTEGER-SQRT just as natural an operation as GCD and LCM when it comes to number theoretical calculations. But this may be a matter of taste. -- Jens Axel Søgaard

**References**:**meta-comment on typing***From:*Per Bothner

**Re: meta-comment on typing***From:*Michael Sperber

**Re: meta-comment on typing***From:*Per Bothner

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