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*To*: Scheme@mc.lcs.mit.edu*Subject*: Scheme Digest #8, Efficiency of Y*From*: cph@kleph.ai.mit.edu (Chris Hanson)*Date*: Wed ,16 Nov 88 06:12:11 EDT*In-reply-to*: Automatic Scheme Digestifier's message of 16 NOV 88 00:11:14 EST*Reply-to*: cph@zurich.ai.mit.edu

Date: Tue, 15 Nov 88 10:26:46 EST From: kranz@wheaties.ai.mit.edu (David Kranz) Edward Wang is correct that the time in the example is dominated by bignum arithmetic. I changed the * in factorial to + and got the following result in T3.1: I tried a similar experiment in MIT Scheme (using + instead of *, except a smaller loop to account for smaller fixnums), with the following results: (factorial-loop 100) -> 1.03 msec (factorial-rec 100) -> 1.0 msec (factorial-lfp 100) -> 2.74 msec Bill Rozas has expended no small effort in the MIT Scheme compiler to make the Y combinator produce good results, and these timings are evidence of that. Still not perfect, but I believe Bill claims that he can make the output code identical given a bit more work.

**Follow-Ups**:**Re: Scheme Digest #8, Efficiency of Y***From:*polya!max@labrea.stanford.edu (Max Hailperin)

**Re: Scheme Digest #8, Efficiency of Y***From:*Krulwich-Bruce@yale-zoo.arpa (Bruce Krulwich)

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