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Re: reading NaNs



 | 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.