Interdisciplinary Information Sciences, Vol. 9, No. 1, pp. 89–94 (2003) An Introduction of Knotscape Yoshiyuki NAKAGAWA Faculty of Economics, Ryukoku University E-mail: [email protected] Received July 1, 2002; final version accepted January 31, 2003 Knotscape is a useful Linux software for supporting the study of knot theory. However, not a few knot theorists give up to use Knotscape, because they do not use Linux. By preparing some files, it is certified that Knotscape can run not only on Linux but also on other operating systems. In this paper, we introduce the installation of Knotscape on other operation system and some additional help information. KEYWORDS: Knotscape, install, FreeBSD, Microsoft Windows 1. What is Knotscape? This paper has two purposes: to introduce the installation of Knotscape and to introduce some additional information of its manual. Knotscape [1] is a Linux freeware programmed by Jim Hoste and Morwen Thistlethwaite for supporting the study of knot theory. You can see its sample screenshot at http://dowker.math.utk.edu/png/screenshot.png. Hoste and Thistlethwaite says about Knotscape in the README file [2] of Knotscape as follows: The original purpose of Knotscape is to provide convenient access to tables of knots. Its purpose has expanded somewhat, particularly with the inclusion of the hyperbolic invariants. The binaries which calculate hyperbolic invariants are compiled against SnapPea 2.0; we are very grateful to Jeff Weeks, the author of SnapPea, for making this possible. We’d like to emphasize that we take full responsibility for any bugs that there might be in the hyperbolic part of Knotscape. At present, Knotscape will deal with knots up to 49 crossings. A database containing all prime knots of up to 16 crossings is included. Dictionaries are included in the doc directory for converting between classical numbering of knots [3] and Dowker–Thistlethwaite numbering. The doc directory also has a subdirectory, called ‘‘symmetric knots’’, containing all highly symmetric knots up to 16 crossings. These can be loaded into Knotscape and investigated. The program requires Tcl 7.4, 7.5, 7.6 or 8.0/Tk 4.0, 4.1, 4.2 or 8.0. Binaries of the executables are provided for the following two platforms: . i386 linux . sunos We can execute Knotscape not only on i386 Linux and SunOS but also on other operating systems. By changing the source a little and by installing some necessary freewares, it is certified that Knotscape can run on the following operating systems: . FreeBSD 2.2.8, 3.0, 3.4, 4.0, 4.3, 4.5 with Linux libraries . Microsoft Windows 98 Second Edition, Me, 2000, XP And also, it is known that Knotscape runs on MacOS. However, the author does not report on Knotscape on MacOS in detail, since the author has no available Macintosh. Acknowledgement We are indebted to Morwen Thistlethwaite for his permission to quote excerpts from Knotsacpe files in this report. We thank to Osamu Monta for giving me a good advice about the installation Knotscape in Microsoft Windows. 2. How to Install 2.1 Machine environment For executing Knotscape, the required specifications of the computer is in the following table: The notations in the table are as follows: Specs means the specifications; CPU means the central processing unit; MHz means mega heltzes, i.e. 106 heltzes; RAM means the random access memory; MB means mega bytes, i.e. 220 bytes; HDD means the hard disk drive; GB means giga bytes, i.e. 230 bytes. The certified specifications is not enough to execute the latest i386 Linux with X Window System. Its certified operating system is only FreeBSD 2.2.8. 90 NAKAGAWA Table 1. Required specifcations of the computer Certified Specs Recommend Specs Clock numbers of CPU 75 MHz 700 MHz over Size of RAM 8 MB 256 MB over Size of HDD 340 MB 2.5 GB over Size of Monitor 640 Â 480 pixels 1024 Â 786 pixels over Buttons of mouse 2 3, or 2 and wheel button If you use either i386 Linux or FreeBSD, install X Window System. If the size of Monitor is less than 1024 Â 786 pixels, you should make the window manager support at least 2 Â 2 screens. If the mouse has only 2 buttons, emulate 3 button mouse by X server or edit the Tcl/Tk script, called linksmith procs.tcl, a little. 2.2 How to install You can download the ‘‘tarball’’ of Knotscape (5 MB over) from Thistlethwaite’s webpage: http:// dowker.math.utk.edu/knotscape.html. The ‘‘tarball’’ is one of the compressed file. The installation of Knotscape in Linux and in SunOS is written in its README file [2] as follows: Installation 1. Download the file knotscape-1.0.<platform>.tar.gz, where <platform> is appropriate for your computer, and copy to the directory where you wish Knotscape to be installed. 2. Untar by typing ‘‘tar zxvf knotscape-1.0.<platform>.tar.gz’’. On some systems the file has to be decompressed with gunzip before untarring with ‘‘tar xvf ...’’ A new directory ‘‘knotscape’’ will appear. 3. Change directory to the new directory ‘‘knotscape’’. 4. If necessary edit the shell script, also called ‘‘knotscape’’, to suit your system. The environment variable KSHOME should be set to the present directory. You may want to choose a different temporary directory from $KSHOME/tmp. This temporary directory is a scratch directory containing all the input and output files generated by the executables. It also contains any PostScript files generated by Knotscape. On some systems the command ‘‘wish’’ needs to be made more specific, as several different versions of Tk might be installed. Knotscape will not run on any version of Tk prior to 4.0. Finally, ensure that all files have the correct permissions. 5. Run Knotscape by typing ‘‘./knotscape’’, or simply ‘‘knotscape’’ if the current working directory is in your PATH variable The following notes are some additional information. The name of the tarball of Knotscape has been altered knotscape-1.01 <platform>.tar.bz2. Hence, if you fail to uncompress, try to untar by typing tar --bzip2 -xvf knotscape-1.01 <platform>.tar.bz2. If you use FreeBSD, do the following procedures in addition. 1. Before installing Knotscape in FreeBSD, install Linux libraries. The easiest way is to use the sysinstall command. 2. Before executing Knotscape, edit the last line of the shell script knotscape by altering ‘‘wish’’ into ‘‘wish<version>’’. If you do not know the version number of wish, you should type wish. Then, you can see the version number, e.g. wish8.0, with a warning. Furthermore, if the version of FreeBSD is 2.2.8, do the following procedures before executing Knotscape. 1. Remove all binaries in the directory $KSHOME/bin. 2. Edit a source, called knotfind.c, in the directory $KSHOME/src for recompiling. Alter ‘‘heapsort’’ in the line 190 and 307 into ‘‘Heapsort’’. 3. Change directory to $KSHOME and recompile all sources by typing make. If you use Microsoft Windows, do the following proceduresÃ. 1. Before installing Knotscape in Microsoft Windows, install cygwin. cygwin is a UNIX environment, developed by RedHat, for Microsoft Windows since Windows 95, with the exception of Windows CE. (a) Jump to http://www.cygwin.com/. (b) Download an installer file http://www.cygwin.com/setup.exe. (c) Install all files by executing the installer. 2. When you download the tarball of Knotscape, <platform> should be selected linuxglibc. And save it at the root directory of the drive, e.g. c:\, that cygwin is installed. Ã This report was one of the best way, when the author introduced Knotscape at Nara Women’s University on November in 2001. Of course, you can execute Knotscape on Microsoft Windows by doing the procedures. However, the author is recommending another way to use KNOPPIX [5] nowadays. An Introduction of Knotscape 91 3. If you do not have any application for Microsoft Windows which can uncompress bzip2 file, execute cygwin for untarring the tarball as follows: (a) Change directory to root by typing cd c:. (b) Untar by typing tar --bzip2 -xvf knotscape 1.01 linuxglibc.tar.bz2. 4. After untarring the tarball, edit the shell script knotscape by using a text editor, e.g. notepad.exe. The environment variable KSHOME should be set by rewriting KSHOME=c:/knotscape 1.01. 5. Before executing Knotscape, execute cygwin and recompile all sources as follows: (a) Delete all binaries in the directory c:/knotscape 1.01/bin. (b) Change directory to c:/knotscape 1.01. (c) Recompile all sources by typing make. 6. If the mouse has only 2 buttons and no wheel, edit the Tcl/Tk script, called linksmith procs.tcl, in the directory c:\knotscape 1.01\tcl as follows: (a) Alter <Button-2> in the line 247 into <Alt-Button-1> (b) Alter <ButtonRelease-2> in the line 248 into <Alt-ButtunRelease-1>. By this edition, you can alter the crossing of diagram in LinkSmith by clicking the left button with pushing the Alt (or Grph) key instead of by clicking the center button (or the wheel button). 3. A Guide of Knotscape You can see the user-friendly manual and tutorial from the Help menu of Knotscape. We extract some essential points of the Help menu and scribe some additional information in this section. 3.1 Coding for knots The contents of this subsection are based on ‘‘Notation for Knots’’ and ‘‘Entering a Knot in the Input Window’’ in the Help menu. In Knotscape, the coding of knots uses the Dowker–Thistlethwaite code. This is an enhanced version of the known notation, called the Gauss notation.