Knotscape 1.01     4-1-99     by Jim Hoste and Morwen Thistlethwaite,
with help from Bruce Ewing, Ken Millett, Ken Stephenson and Jeff Weeks.

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Features added since Version 1.0:

(1)  LinkSmith has a new "Export" menu,   with two options:
  (i) save the current link diagram in Ewing-Millett format;
  (ii) save the underlying link complement as an ideal
  triangulation, in SnapPea-readable format.

(2)  The horoball and drawing windows now have an option invoking
a file-save dialogue box for saving the picture as a PostScript file.

(3)  Hyperbolic invariants now occupy a separate (tear-off) submenu
of the Action menu.  There are two new features:
  (i) "Save Triangulation", which produces an ideal triangulation of
  the (hyperbolic) knot complement, and writes it to a file in
  SnapPea-readable format;
  (ii) "Canonical Cell Decomposition", which displays the canonical
  cell decomposition of the knot complement, as viewed from the cusp.
The canonical cell decomposition can be saved as a PostScript file.
It is a complete invariant of cusped hyperbolic manifolds.  For
further details, see the Help file on hyperbolic invariants.

Some bug fixes are listed in the file FIXES.

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README for Version 1.0

Please see the file Credits.ps for details on contributors
to Knotscape.

This version is an upgrade to Knotscape 1.0-BETA.

The main enhancement is the incorporation of LinkSmith,
a program enabling the user to draw a knot with a mouse.
Also, Knotscape now includes in its database all knots up
to 16 crossings.  Various other minor improvements have been
made since the beta version.

The original purpose of Knotscape was 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 were 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 and Dowker-Thistlethwaite numbering.
The doc directory also has a subdirectory "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

Source code is also provided in each version for all but one of
the executables.

The procedures not dependant on SnapPea can be compiled in a
straightforward manner, using the Makefile in Knotscape's home
directory.  But we have not yet tested Knotscape on any platform
except those listed above, so it is likely that there would be
problems.

The program knotscape_hyp.c can also be compiled against
Snappea-2.0, downloadable from Jeff Weeks's home page at
http://thames.northnet.org/weeks/ .
knotscape_hyp.c provides all the SnapPea functions in Knotscape
except for the computation of fixed point sets of symmetries,
and the computation of the canonical dell decomposition.
The program  knotscape_hyp.c refers to procedures in
decode_new_DT.c, also in the src directory.

The source code for computation of fixed point sets and the
canonical decomposition is not yet supplied, as the two programs
in question have to be compiled against non-standard versions of
the SnapPea kernel.  Hopefully these will also be available in
the near future.

We welcome any suggestions for improvements, and also of course
reports of bugs.

Jim Hoste <[email protected]>
Morwen Thistlethwaite <[email protected]>


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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.


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Getting started.


The easiest way of getting started is to use the browser window to
enter one or more knots in the input window.  A tutorial can be
accessed by clicking on "HELP" followed by "Tutorial".

It's possible that machines with no swap partition or machines with
a small amount of memory will produce a segmentation violation when
some of Knotscape's options are invoked.  If you are using a Linux
machine, the solution is to create a suitably large swap partition.


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