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| From: Bradley Lucier <lucier@xxxxxxxxxxxxxxx> | Date: Fri, 28 Oct 2005 00:25:46 -0500 | | On Oct 24, 2005, at 3:32 PM, Aubrey Jaffer wrote: | | > ;;;; integer-sqrt attributed to Bradley Lucier by Steve VanDevender. | | I didn't invent this method, I got it from | | http://www.cs.cmu.edu/afs/cs/project/ai-repository/ai/lang/lisp/code/math/isqrt/isqrt.txt | | as the thread in Google Groups shows. Thanks for the correction. I changed the attribution to: Akira Kurihara School of Mathematics Japan Women's University | This method is about half as fast as the method in | | ;; Derived from the paper "Karatsuba Square Root" by Paul Zimmermann, | ;; INRIA technical report RR-3805, 1999. (Used in gmp 4.*) | | basically because Zimmermann's method's final divide is half the size | of the final divide of the previous method. The Kurihara algorithm in portable R5RS Scheme is now in SLIB (http://savannah.gnu.org/cgi-bin/viewcvs/slib/slib/root.scm?rev=HEAD&content-type=text/vnd.viewcvs-markup). If someone contributes Zimmermann's algorithm coded in R5RS Scheme and it is faster in several implementations, then SLIB will incorporate it.