Unable to use KnotTheory

Question

I've installed the KnotTheory package, following the instructions here. But when I try to use it I get this error:

$CharacterEncoding: The byte sequence {139} could not be interpreted as a character in the UTF-8 character encoding.

Both << KnotTheory` and Needs["KnotTheory`"] raise this error (I found that byte sequence {139} is for "<"). "Needs" also raises

Needs: "Context KnotTheory` was not created when Needs was evaluated".

Parent directory of KnotTheory is in the $Path, but it doesn't help.

How can I fix it?

Answer 1

I recall that Claus Ernst once asked me about that. It's time that we make the fix public and searchable:

Go into the file init.m on the KnotTheory package directory. Then replace the lines

KnotTheoryDirectory[] = (
  File /. Flatten[FileInformation[ToFileName[#,"KnotTheory"]] & /@ ($Path /. "." -> Directory[])]
)

with

KnotTheoryDirectory[] = DirectoryName[$InputFileName];

Save the file, restart the kernel. Afterwards, the package should load just fine.

Answer 2

I just tried it. It works for me, it loads and I can call its functions, but I keep getting warning Get::path: ParentDirectory[File] in $Path is not a string. even though it does give the same output as on the web site.

I think you need to edit init.m to fix these. It seems like old package.

There are the steps I did

download zip file. Extract the folder KnotTheory. Then did

FileNameJoin[{$UserBaseDirectory,"Applications"}]

Which gives

"C:\\Users\\Owner\\AppData\\Roaming\\Mathematica\\Applications"

Then copied the folder KnotTheory to the above folder. So now it looks like this

Now from Mathematica

Quit[]

<< KnotTheory`

Gives these warnings

But it works

 Alexander[Knot[6, 2]][t]

I never used this package myself before. But the date on the webpage is 2013, which is old.