Ralph William (Bill) Gosper, Jr.,
an American mathematician and computer scientist, along with Richard Greenblatt considered the co-founder of the hacker community ^{[1]} .

HAKMEM, alternatively known as AI Memo 239, is a February 1972 "memo" (technical report) of the MITAI Lab by Gosper et al. that describes a wide variety of hacks, primarily useful and clever algorithms^{[8]}, and even a chess position ^{[9]}^{[10]}. A few samples, referred elsewhere:

HAKMEM 70

HAKMEM 70 ^{[11]}, A neat chess problem, swiped from Chess for Fun and Chess for Blood, by Edward Lasker^{[12]}. White mates in three moves:

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

Home * People * Bill GosperRalph William (Bill) Gosper, Jr.,an American mathematician and computer scientist, along with Richard Greenblatt considered the co-founder of the hacker community

^{[1]}.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

^{[2]}. Bill Gosper created numerous packing problem puzzles such as the Twubblesome Twelve^{[3]}, 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^{[4]}.^{[5]}## Table of Contents

## Robert Q

^{[6]}^{[7]}## 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^{[8]}, and even a chess position^{[9]}^{[10]}. A few samples, referred elsewhere:## HAKMEM 70

HAKMEM 70^{[11]}, A neat chess problem, swiped fromChess for Fun and Chess for Blood, by Edward Lasker^{[12]}. White mates in three moves:## HAKMEM 169

HAKMEM 169, to count the ones in a PDP-6/PDP-10 36-bit word, written in Assembly^{[13]}^{[14]}:## HAKMEM 175

HAKMEM 175 - next higher number with the same number of one bits (Snoob), by Bill Gosper, PDP-6 Assembly^{[15]}:## Gosper's Glider Gun

^{[16]}## See also

## Selected Publications

1972).HAKMEM, Memo 239, Artificial Intelligence Laboratory, Massachusetts Institute of Technology^{[17]}1977).Decision procedure for indefinite hypergeometric summation. Proc. Natl. Acad. Sci. USA, Vol. 75, No. 1, pdf^{[18]}## External Links

Rep-tiles by Bill Gosper

HAKMEMC -- HAKMEM Programming hacks in C by Alan Mycroft

## References

MIT Computer Loses to Human in Chess. Sun Journal (Lewiston), January 23, 1967, Google News1972).HAKMEM, Memo 239, Artificial Intelligence Laboratory, Massachusetts Institute of Technology1942,1962)Chess for Fun and Chess for Blood. Dover Publications; 2 edition, ISBN-13: 978-0486201467, amazon## What links here?

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