tierra.doc

地球模拟器

/* TIERRA.DOC  9-9-92  documentation for the Tierra Simulator */
/* Tierra Simulator V4.0: Copyright (c) 1991, 1992 Tom Ray & Virtual Life */

This file contains the following sections:

1)  LICENSE AGREEMENT
2)  WHAT THIS PROGRAM IS, PUBLICATIONS, NEWS
3)  RELATED SOFTWARE (IMPORTANT)
4)  QUICK START   <-------------- You might want to start here! 
  4.1) DOS QUICK START
  4.2) UNIX QUICK START
5)  RUNNING TIERRA
  5.1) Startup
  5.2) The Assembler/Disassembler
  5.3) The Birth-Death Output
  5.4) The Genebank Output
  5.5) Restarting an Old Run
  5.6) The User Interface
    5.6.1) The Basic Interface
      5.6.1.1) The Basic Screen
      5.6.1.2) The Menu Options
        5.6.1.2.1) The Size Histogram
        5.6.1.2.2) The Memory Histogram
        5.6.1.2.3) The Genotype Histogram
        5.6.1.2.4) The Size Class Information Display
        5.6.1.2.5) The Virtual Debugger
        5.6.1.2.6) The Genome Injector
    5.6.2) The Standard Output
    5.6.3) The tierra.log file
6)  LISTING OF DISTRIBUTION FILES
7)  SOUP_IN PARAMETERS (IMPORTANT)
8)  THE INSTRUCTION SETS
  8.1) Synopsis of the Four Sets
  8.2) Details of Set 1
  8.3) New Features in Sets 2 through 4
9)  THE ANCESTOR & WRITING A CREATURE
  9.1) The Ancestor
  9.2) Writing a Creature
10) IF YOU WANT TO MODIFY THE SOURCE CODE
  10.1) Creating a Frontend
  10.2) Creating New Instruction Sets
  10.3) Creating New Slicer Mechanisms
  10.4) Creating a Sexual Model
  10.5) Creating a Multi-cellular Model
11) CONFIGURATION AT COMPILE TIME (configur.h)
12) KNOWN BUGS
13) IF YOU HAVE PROBLEMS
  13.1) Problems with Installation
  13.2) Problems Running Tierra
14) REGISTRATION & MAILING LISTS

1)  LICENSE AGREEMENT

/* 
 * Tierra Simulator V4.0: Copyright (c) 1990, 1991, 1992 Thomas S. Ray
 * 
 * by Tom Ray, [e-mail] [e-mail] (the bulk of the code)
 *    Dan Pirone, [e-mail] (frontend, overhaul, sex)
 *    Tom Uffner, [e-mail] (rework of genebanker & assembler)
 * 
 * If you purchased this program on disk, thank you for your support.  If 
 * you obtained the source code through the net or friends, we invite you to
 * contribute an amount that represents the program's worth to you.  You may
 * make a check in US dollars payable to Virtual Life, and mail the check to
 * one of the two addresses listed below.
 * 
 * This license agreement has two parts: 
 * 
 * 1) The source code, documentation, and the beagle.exe file can be freely
 *    distributed.
 * 
 * 2) The executables (the .exe files in DOS) are for sale and can not be
 *    freely distributed (with the exception of the beagle.exe file).
 *    Executables (binaries) on any platform (Unix, Mac, Amiga, DOS, etc.)
 *    can not be freely distributed.
 * 
 * These two points are elaborated below:
 * 
 * 1) The source code, documentation, and the beagle.exe file can be freely
 *    distributed.
 * 
 * The source code and documentation is copyrighted, all rights reserved.
 * The source code, documentation, and the beagle.exe file may be freely
 * copied and distributed without fees (contributions welcome), subject to
 * the following restrictions:
 * 
 * - This notice may not be removed or altered.
 * 
 * - You may not try to make money by distributing the package or by using the
 *   process that the code creates.
 * 
 * - You may not prevent others from copying it freely.
 * 
 * - You may not distribute modified versions without clearly documenting your
 *   changes and notifying the principal author.
 * 
 * - The origin of this software must not be misrepresented, either by
 *   explicit claim or by omission.  Since few users ever read sources,
 *   credits must appear in the documentation.
 * 
 * - Altered versions must be plainly marked as such, and must not be
 *   misrepresented as being the original software.  Since few users ever read
 *   sources, credits must appear in the documentation.
 * 
 * 2) The executables (the .exe files in DOS) are for sale and can not be
 *    freely distributed (with the exception of the beagle.exe file).
 *    Executables (binaries) on any platform (Unix, Mac, Amiga, DOS, etc.)
 *    can not be freely distributed.
 * 
 * The executables (the .exe files in DOS) are copyrighted, all rights
 * reserved.  You should treat this software just like a book.  This means
 * that this software (the executables) may be used by any number of people
 * and may be freely moved from one computer to another so long as the program
 * is not used by more than one person at a time.  This applies to binaries on
 * any platform.
 * 
 *   The following provisions also apply in both cases 1 and 2: 
 * 
 * - Virtual Life and the authors are not responsible for the consequences of
 *   use of this software, no matter how awful, even if they arise from flaws
 *   in it.
 * 
 * - Neither the name of Virtual Life, nor the authors of the code may be used
 *   to endorse or promote products derived from this software without
 *   specific prior written permission.
 * 
 * - The provision of support and software updates is at our discretion.
 * 
 * Please contact Tom Ray (full address below) if you have questions or would
 * like an exception to any of the above restrictions.
 * 
 * If you make changes to the code, or have suggestions for changes,
 * let us know!  If we use your suggestion, you will receive full credit
 * of course.
 * 
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 *    Tom Ray
 *
 *    Virtual Life              (September through December)
 *    P.O. Box 625
 *    Newark, Delaware  19715
 *
 *    School of Life & Health Sciences
 *    University of Delaware
 *    Newark, DE  19716
 *
 *    [e-mail] (email)
 *    302-831-2753 (Phone)
 *    302-831-2281 (Fax)
 *
 *    or
 *
 *    Santa Fe Institute        (January through August)
 *    1660 Old Pecos Trail
 *    Suite A
 *    Santa Fe, NM 87501
 *
 *    [e-mail] (email)
 *    505-984-8800 (Phone)
 *    505-982-0565 (Fax)
 */

2)  WHAT THIS PROGRAM IS, PUBLICATIONS, NEWS

     The C source code creates a virtual computer and its operating system,
whose architecture has been designed in such a way that the executable
machine codes are evolvable.  This means that the machine code can be mutated
(by flipping bits at random) or recombined (by swapping segments of code
between algorithms), and the resulting code remains functional enough of the
time for natural (or presumably artificial) selection to be able to improve
the code over time.

     Along with the C source code which generates the virtual computer, we
provide several programs written in the assembler code of the virtual
computer.  Some of these were written by a human and does nothing more than
make copies of itself in the RAM of the virtual computer.  The others evolved
from the first, and are included to illustrate the power of natural selection.

     The virtual machine is an emulation of a MIMD (multiple instruction
stream, multiple data stream) computer.  This is a massively parallel computer
in which each processor is capable of executing a sequence of operations
distinct from the other processors.  The parallelism is only emulated by
time slicing, but there really are numerous virtual CPUs.  One CPU will be
created and assigned to each ``creature'' (self-replicating algorithm)
living in the RAM of the virtual computer.  The RAM of the virtual computer
is known as the ``soup''.

     The operating system of the virtual computer provides memory management
and timesharing services.  It also provides control for a variety of factors
that affect the course of evolution: three kinds of mutation rates,
disturbances, the allocation of CPU time to each creature, the size of the
soup, the spatial distribution of creatures, etc.  In addition, the operating
system provides a very elaborate observational system that keeps a record of
births and deaths, sequences the code of every creature, and maintains a
genebank of successful genomes.  The operating system also provides facilities
for automating the ecological analysis, that is, for recording the kinds of
interactions taking place between creatures.

     The version of the software currently being distributed is considered
to be a research grade implementation.  This means two things: 1) It is
under very rapid development, and may not be completely bug free.  2) We have
chosen to go with modifiability and modularity over speed of execution.

     If you find bugs in the code, please report them to us.  By the time
you find them and report them, we may have eliminated them, and would be
able to provide you with a fixed version.  If not, we will be able to fix
the bug, and would like to make the fix available to other users.

     We have chosen modifiability over speed primarily because we know that
the original version of the virtual computer was very poorly designed, except
with respect to the features that make it evolvable.  Specifically, consider
that one third of the original instruction set is taken up by pushing and
popping from the stack; there are only two inter-register moves, ax to bx and
cx to dx; dx isn't used for anything (in the initial version, dx was used to
set the template size, but that has been abandoned); there are no moves
between CPU registers and RAM; there is no I/O; and there is no way of
addressing a data segment.

     In August 1991, 100% of the original virtual CPU code was replaced, with
new code that does exactly the same thing.  However, the new code is written
in a generalized way, a meta-virtual computer, that makes it trivial to
alter the machine architecture.  With the new implementation of the virtual
computer, it is possible for anyone to painlessly swap in their favorite
CPU architecture and instruction set, and their innovation will be seamlessly
embedded within the heart of the elaborate observational software.  Knowing
how bad the original design was, there was a temptation to fix it when the
virtual computer was reworked, but the original implementation was retained
for historical reasons.  In spite of its shortcomings, life proliferated in
the environment that it created.  Things should get interesting as we improve
the architecture.  The new organization of the code should make that easy.

     In August of 1992, the modifications of the previous August bore fruit
as three new instruction sets were implemented.  These are documented in some
detail below, and in general, eliminate most of the problems discussed
above.

     The bulk of the code and documentation was written by Tom Ray, whose
address is listed at the end of this file.  Substantial contributions have
been made by: Dan Pirone, [e-mail], has been involved in
the Tierra project since the Fall of 1990.  Dan began working full
time on Tierra in February 1992.  Dan has written the user interface,
and has been working on a phylogeny tool that should be completed by
October of 1992.  Tom Uffner, [e-mail], reworked the genebanker
and assembler/disassembler in the Fall of 1991.  Marc Cygnus,
[e-mail], developed the ALmond monitor, a separate piece
of software that displays activity in a running Tierra (see below).

     The behavior of this software is described in the following publications:

Ray, T. S.  1991.  ``Is it alive, or is it GA?''
Proceedings of the 1991 International Conference on Genetic Algorithms,
Eds. Belew, R. K., and L. B. Booker, San Mateo, CA: Morgan Kaufmann, 527-534.

Ray, T. S.  1991.  ``An approach to the synthesis of life.''
Artificial Life II, Santa Fe Institute Studies in the Sciences of
Complexity, vol. XI, Eds. Farmer, J. D., C. Langton, S. Rasmussen, &
C. Taylor, Redwood City, CA: Addison-Wesley, 371-408.

Ray, T. S.  1991.  ``Population dynamics of digital organisms.''
Artificial Life II Video Proceedings,  Ed. C.G. Langton,
Redwood City, CA: Addison Wesley.

Ray, T. S.  1991.  ``Evolution and optimization of digital organisms.''
Scientific Excellence in Supercomputing: The IBM 1990 Contest Prize
Papers, Eds. Keith R. Billingsley, Ed Derohanes, Hilton Brown, III.
Athens, GA, 30602, The Baldwin Press, The University of Georgia.

Ray, T. S.  1992.  ``Evolution ecology and optimization of digital organisms.''
Santa Fe Institute working paper (available in the ftp site as tierra.tex
and tierra.ps).

The Tierra Simulator has been widely reported in the media.  Below is a
list of most of the national or international reports that I am aware of.
If you know of some news report not on this list, please send me a hard
copy.

Nature (John Maynard Smith, UK) February 27, 1992: ``Byte-sized evolution.
...we badly need a comparative biology.  So far, we have been able to study
only one evolving system and we cannot wait for interstellar flight to
provide us with a second.  If we want to discover generalizations about
evolving systems, we will have to look at artificial ones.  Ray's study is a
good start.''

Science (Mitchell Waldrop, USA) August 21, 1992: ``Artificial Life's Rich
Harvest, Startlingly realistic simulations of organisms, ecosystems, and
evolution are unfolding on computer screens as researchers try to recreate
the dynamics of living things.''

New York Times (Malcolm Browne, USA) August 27, 1991: ``Lively Computer
Creation Blurs Definition of Life.  Software forms, obeying Darwin's rules,
vie to avoid the `reaper'.''