Bill+Gosper

an American mathematician and computer scientist, along with Richard Greenblatt considered the co-founder of the [|hacker] community.
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 * [[image:BillGosper.jpg width="233" height="262" link="http://en.wikipedia.org/wiki/File:Bill_Gosper_2006.jpg"]] ||~  || **Ralph William (Bill) Gosper, Jr.**,

In the 60s, affiliated with MIT, he worked for [|Project MAC] (Machine-Aided Cognition), where his contributions to [|computational mathematics] and Bit-Twiddling include HAKMEM and Maclisp. He helped Greenblatt with his chess program Mac Hack VI, and operated the PDP-6 when Robert Q played its first tournament game versus Carl Wagner.

In the 70s, Bill Gosper moved to Stanford University for some years, where he lectured and helped Donald Knuth to write volume II of [|The Art of Computer Programming]. He has worked at or consulted for [|Xerox PARC], [|Symbolics], [|Wolfram Research], the Lawrence Livermore National Laboratory, and [|Macsyma]. Bill Gosper created numerous [|packing problem] puzzles such as the Twubblesome Twelve, and was interested in the Conway's [|Game of Life], where he found the [|Glider Gun] and originated the [|Hashlife] algorithm to speed up the computation of Life patterns. || toc =Robert Q= =HAKMEM= [|HAKMEM], alternatively known as [|AI Memo] 239, is a February 1972 "memo" (technical report) of the MIT [|AI Lab] by Gosper et al. that describes a wide variety of [|hacks], primarily useful and clever algorithms, and even a chess position. A few samples, referred elsewhere: 
 * Bill Gosper 2006 ||~  ||^   ||
 * [[image:RobertQ1967.JPG width="500" link="http://news.google.com/newspapers?nid=1928&dat=19670123&id=O2ggAAAAIBAJ&sjid=1GYFAAAAIBAJ&pg=2308,2313204"]] ||
 * [|Allen Moulton] and R. William Gosper operating "Robert Q" on a PDP-6 ||

HAKMEM 70
HAKMEM 70, A neat chess problem, swiped from //Chess for Fun and Chess for Blood//, by [|Edward Lasker]. White mates in three moves: 
 * [[image:http://webchess.freehostia.com/diag/chessdiag.php?fen=5B2/6P1/1p6/8/1N6/kP6/2K5/8%20w%20-%20-&size=large&coord=yes&cap=no&stm=yes&fb=no&theme=classic&color1=E3CEAA&color2=635147&color3=000000]] ||
 * = 5B2/6P1/1p6/8/1N6/kP6/2K5/8 w - - ||

HAKMEM 169
HAKMEM 169, to count the ones in a PDP-6/PDP-10 36-bit word, written in Assembly : code LDB  B,[014300,,A]     ;or MOVE B,A then LSH B,-1 AND  B,[333333,,333333] SUB  A,B LSH  B,-1 AND  B,[333333,,333333] SUBB A,B               ;each octal digit is replaced by number of 1's in it   LSH   B,-3 ADD  A,B AND  A,[070707,,070707] IDIVI A,77             ;casting out 63.'s code 

HAKMEM 175
HAKMEM 175 - next higher number with the same number of one bits (Snoob), by Bill Gosper, PDP-6 Assembly : code MOVE B,A MOVN C,B AND  C,B ADD  A,C MOVE D,A XOR  D,B LSH  D,-2 IDIVM D,C IOR  A,C code =Gosper's Glider Gun= =See also=
 * [[image:Gospers_glider_gun.gif width="480" link="http://en.wikipedia.org/wiki/File:Gospers_glider_gun.gif"]] ||
 * Gosper's [|Glider Gun] in action — a variation of Conway's [|Game of Life] ||
 * Bit-Twiddling
 * Mac Hack VI
 * PDP-6
 * Traversing Subsets of a Set

=Selected Publications=
 * Michael Beeler, Bill Gosper, [|Rich Schroeppel] (**1972**). //[|HAKMEM]//, Memo 239, Artificial Intelligence Laboratory, Massachusetts Institute of Technology
 * Bill Gosper (**1977**). //Decision procedure for indefinite hypergeometric summation//. Proc. Natl. Acad. Sci. USA, Vol. 75, No. 1, [|pdf]

=External Links= > [|Rep-tiles] by Bill Gosper > [|HAKMEMC -- HAKMEM Programming hacks in C] by [|Alan Mycroft]
 * [|Bill Gosper from Wikipedia]
 * [|Twubblesome Twelve - a difficult puzzle] by Bill Gosper
 * [|HAKMEM from Wikipedia]
 * [|Gosper's algorithm from Wikipedia]
 * [|Gosper curve from Wikipedia]
 * [|Hashlife from Wikipedia] by Bill Gosper

=References= =What links here?= include page="Bill Gosper" component="backlinks" limit="40"
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