Bill Gosper

Last updated
Ralph William Gosper Jr.
Bill Gosper 2006.jpg
Born (1943-04-26) April 26, 1943 (age 80)
NationalityAmerican
Alma mater Massachusetts Institute of Technology
Occupation(s)Programmer, Computer scientist, Mathematician
Organizations Xerox PARC, Symbolics, Wolfram Research, the Lawrence Livermore Laboratory, Macsyma, Inc.
Known for Gosper curve, Gosper Glider Gun, Gosper's algorithm, Hashlife

Ralph William Gosper Jr. (born April 26, 1943), known as Bill Gosper, is an American mathematician and programmer. [1] Along with Richard Greenblatt, he may be considered to have founded the hacker community, and he holds a place of pride in the Lisp community. [2] The Gosper curve and the Gosper's algorithm are named after him.

Contents

Becoming a hacker

In high school, Gosper was interested in model rockets until one of his friends was injured in a rocketry accident and contracted a fatal brain infection. [3] Gosper enrolled in MIT in 1961, and he received his bachelor's degree in mathematics from MIT in 1965 despite becoming disaffected with the mathematics department because of their anti-computer attitude. [3]

In his second year at MIT, Gosper took a programming course from John McCarthy and became affiliated with the MIT AI Lab.

His contributions to computational mathematics include HAKMEM and the MIT Maclisp system. He made major contributions to Macsyma, Project MAC's computer algebra system. Gosper later worked with Symbolics and Macsyma, Inc. on commercial versions of Macsyma.

In 1974, he moved to Stanford University, where he lectured and worked with Donald Knuth. [3]

Since that time, he has worked at or consulted for Xerox PARC, Symbolics, Wolfram Research, the Lawrence Livermore Laboratory, and Macsyma Inc.

Key contributions

Conway's Game of Life

He became intensely interested in the Game of Life shortly after John Horton Conway had proposed it. Conway conjectured the existence of infinitely growing patterns, and offered a reward for an example. Gosper was the first to find such a pattern, the glider gun, and won the prize. [4] Gosper was also the originator of the Hashlife algorithm that can speed up the computation of Life patterns by many orders of magnitude.

Packing problems

Gosper has created numerous packing problem puzzles, such as "Twubblesome Twelve". [5]

Symbolic computation

Gosper was the first person to realize the possibilities of symbolic computation on a computer as a mathematics research tool,[ citation needed ] whereas computer methods were previously limited to purely numerical methods. In particular, this research resulted in his work on continued fraction [6] representations of real numbers and Gosper's algorithm for finding closed form hypergeometric identities.

In 1985, Gosper briefly held the world record for computing the most digits of pi with 17 million digits. [7] See chronology of computation of π.

Space-filling curves

In the continuity of early 20th century examples of space-filling curves—the Koch-Peano curve, Cesàro and Lévy C curve, all special cases of the general de Rham curve—and following the path of Benoit Mandelbrot, Gosper discovered the Peano-Gosper curve, before engaging with variations on the Harter-Heighway dragon. [8] In the late 80s, Gosper independently discovered the Gosper-Lafitte triangle. [9]

See also

Related Research Articles

The number π is a mathematical constant that is the ratio of a circle's circumference to its diameter, approximately equal to 3.14159. The number π appears in many formulae across mathematics and physics. It is an irrational number, meaning that it cannot be expressed exactly as a ratio of two integers, although fractions such as are commonly used to approximate it. Consequently, its decimal representation never ends, nor enters a permanently repeating pattern. It is a transcendental number, meaning that it cannot be a solution of an equation involving only sums, products, powers, and integers. The transcendence of π implies that it is impossible to solve the ancient challenge of squaring the circle with a compass and straightedge. The decimal digits of π appear to be randomly distributed, but no proof of this conjecture has been found.

<span class="mw-page-title-main">Conway's Game of Life</span> Two-dimensional cellular automaton devised by J. H. Conway in 1970

The Game of Life, also known simply as Life, is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is a zero-player game, meaning that its evolution is determined by its initial state, requiring no further input. One interacts with the Game of Life by creating an initial configuration and observing how it evolves. It is Turing complete and can simulate a universal constructor or any other Turing machine.

<span class="mw-page-title-main">Koch snowflake</span> Fractal curve

The Koch snowflake is a fractal curve and one of the earliest fractals to have been described. It is based on the Koch curve, which appeared in a 1904 paper titled "On a Continuous Curve Without Tangents, Constructible from Elementary Geometry" by the Swedish mathematician Helge von Koch.

A computer algebra system (CAS) or symbolic algebra system (SAS) is any mathematical software with the ability to manipulate mathematical expressions in a way similar to the traditional manual computations of mathematicians and scientists. The development of the computer algebra systems in the second half of the 20th century is part of the discipline of "computer algebra" or "symbolic computation", which has spurred work in algorithms over mathematical objects such as polynomials.

Experimental mathematics is an approach to mathematics in which computation is used to investigate mathematical objects and identify properties and patterns. It has been defined as "that branch of mathematics that concerns itself ultimately with the codification and transmission of insights within the mathematical community through the use of experimental exploration of conjectures and more informal beliefs and a careful analysis of the data acquired in this pursuit."

In symbolic computation, the Risch algorithm is a method of indefinite integration used in some computer algebra systems to find antiderivatives. It is named after the American mathematician Robert Henry Risch, a specialist in computer algebra who developed it in 1968.

Macsyma is one of the oldest general-purpose computer algebra systems still in wide use. It was originally developed from 1968 to 1982 at MIT's Project MAC.

Axiom is a free, general-purpose computer algebra system. It consists of an interpreter environment, a compiler and a library, which defines a strongly typed hierarchy.

HAKMEM, alternatively known as AI Memo 239, is a February 1972 "memo" of the MIT AI Lab containing a wide variety of hacks, including useful and clever algorithms for mathematical computation, some number theory and schematic diagrams for hardware – in Guy L. Steele's words, "a bizarre and eclectic potpourri of technical trivia". Contributors included about two dozen members and associates of the AI Lab. The title of the report is short for "hacks memo", abbreviated to six upper case characters that would fit in a single PDP-10 machine word.

<span class="mw-page-title-main">Hashlife</span> Algorithm for speeding up cellular automaton simulations

Hashlife is a memoized algorithm for computing the long-term fate of a given starting configuration in Conway's Game of Life and related cellular automata, much more quickly than would be possible using alternative algorithms that simulate each time step of each cell of the automaton. The algorithm was first described by Bill Gosper in the early 1980s while he was engaged in research at the Xerox Palo Alto Research Center. Hashlife was originally implemented on Symbolics Lisp machines with the aid of the Flavors extension.

In calculus, symbolic integration is the problem of finding a formula for the antiderivative, or indefinite integral, of a given function f(x), i.e. to find a differentiable function F(x) such that

Joel Moses was an Israeli-American mathematician, computer scientist, and Institute Professor at the Massachusetts Institute of Technology (MIT).

Approximations of <span class="texhtml mvar" style="font-style:italic;">π</span> Varying methods used to calculate π

Approximations for the mathematical constant pi in the history of mathematics reached an accuracy within 0.04% of the true value before the beginning of the Common Era. In Chinese mathematics, this was improved to approximations correct to what corresponds to about seven decimal digits by the 5th century.

Symbolic Manipulation Program, usually called SMP, was a computer algebra system designed by Chris A. Cole and Stephen Wolfram at Caltech circa 1979. It was initially developed in the Caltech physics department with contributions from Geoffrey C. Fox, Jeffrey M. Greif, Eric D. Mjolsness, Larry J. Romans, Timothy Shaw, and Anthony E. Terrano.

<span class="mw-page-title-main">Steve Omohundro</span> American computer scientist

Stephen Malvern Omohundro is an American computer scientist whose areas of research include Hamiltonian physics, dynamical systems, programming languages, machine learning, machine vision, and the social implications of artificial intelligence. His current work uses rational economics to develop safe and beneficial intelligent technologies for better collaborative modeling, understanding, innovation, and decision making.

Paterson's worms are a family of cellular automata devised in 1971 by Mike Paterson and John Horton Conway to model the behaviour and feeding patterns of certain prehistoric worms. In the model, a worm moves between points on a triangular grid along line segments, representing food. Its turnings are determined by the configuration of eaten and uneaten line segments adjacent to the point at which the worm currently is. Despite being governed by simple rules the behaviour of the worms can be extremely complex, and the ultimate fate of one variant is still unknown.

In mathematics, Gosper's algorithm, due to Bill Gosper, is a procedure for finding sums of hypergeometric terms that are themselves hypergeometric terms. That is: suppose one has a(1) + ... + a(n) = S(n) − S(0), where S(n) is a hypergeometric term (i.e., S(n + 1)/S(n) is a rational function of n); then necessarily a(n) is itself a hypergeometric term, and given the formula for a(n) Gosper's algorithm finds that for S(n).

<span class="mw-page-title-main">Computer algebra</span> Scientific area at the interface between computer science and mathematics

In mathematics and computer science, computer algebra, also called symbolic computation or algebraic computation, is a scientific area that refers to the study and development of algorithms and software for manipulating mathematical expressions and other mathematical objects. Although computer algebra could be considered a subfield of scientific computing, they are generally considered as distinct fields because scientific computing is usually based on numerical computation with approximate floating point numbers, while symbolic computation emphasizes exact computation with expressions containing variables that have no given value and are manipulated as symbols.

<span class="mw-page-title-main">Wolfram Language</span> Programming language and environment developed by Wolfram Research

The Wolfram Language is a proprietary, general high-level multi-paradigm programming language developed by Wolfram Research. It emphasizes symbolic computation, functional programming, and rule-based programming and can employ arbitrary structures and data. It is the programming language of the mathematical symbolic computation program Mathematica.

<span class="mw-page-title-main">Paul S. Wang</span> Chinese-American computer scientist (born 1944)

Paul S. Wang is a Chinese-American computer scientist, researcher, author, consultant, and academic. He is Professor Emeritus of Computer Science at Kent State University.

References

  1. Bill Gosper Archived January 10, 2008, at the Wayback Machine , Vintage Computer Festival. Accessed January 3, 2007.
  2. Levy, Steven, Hackers: Heroes of the Computer Revolution , (1984)
  3. 1 2 3 Albers, Donald J.; Alexanderson, Gerald L.; Reid, Constance, eds. (1990), "Bill Gosper", More Mathematical People, Harcourt Brace Jovanovich, pp. 100–117.
  4. Gardner, Martin (2001). The Colossal Book of Mathematics. New York: W. W. Norton. ISBN   0-393-02023-1.
  5. Rucker, Rudy (2012). Nested Scrolls: The Autobiography of Rudolf Von Bitter Rucker. Macmillan. p. 240. ISBN   978-0-76532753-6.
  6. Gosper, Bill. "Continued Fraction Arithmetic" . Retrieved August 2, 2018.
  7. Arndt, Jörg; Haenel, Christoph (2006). Pi Unleashed. Springer-Verlag. pp. 104, 206. ISBN   978-3-540-66572-4. English translation by Catriona and David Lischka. Record was in 1985.
  8. Gosper, Bill. "Plane-Filling Functions vs. Space-Filling Curves". YouTube . Retrieved November 1, 2019.
  9. "Distribution of nonempty triangles inside a fractal rep-4-tile". The On-Line Encyclopedia of Integer Sequences. 1995.