Wednesday, July 17, 2019

Version 0.931a online (MacOS surgery bug located!)

Just a quick note that the MacOS KLO bug for surgery diagrams has now been resolved, and Version 0.931a is online with that fixed (Windows version remains unchanged)!  Many thanks to Geoffrey Sangston for sending me a document producing the crash, which makes such issues much easier to identify!

For any techies or those curious: for some reason, the Boost cpp_rational constructor is throwing an an exception in the MacOS build if you try to construct a rational number with a negative denominator (!), instead of just negating the numerator and denominator and continuing happily along.  Strange...

Sunday, July 14, 2019

Welcome, ICERM participants!

Welcome to ICERM workshop participants (thanks to Ken Baker for the publicity)!  Please subscribe to this blog (on the right) to be kept up to date on new versions and features, as we move toward version 1.0.

I've been pretty bad about announcing new features and updates up to now, without a central spot to put the announcements (apologies!); this blog should help out as a central spot.

Also, please note that is going away as a domain, in favor of

Saturday, July 13, 2019

KLO 0.93a

Moving toward version 1.0, KLO 0.93a is now online at
  • New knots can now be entered via Dowker codes, either the traditional space-separated list of even number (negative to reverse crossings) or via the shorter codes (bca = 4 6 2) using lower-case letters without spaces (uppercase to reverse crossings).
  • A new Convert menu that houses what used to be in buttons to convert between surgery and Kirby diagrams and to generate Kirby diagrams for 2-fold branched covers of knots, as well as a new feature to clone a diagram into a new document considering it as a plain old knot, allowing hyperbolic comparisons (via the SnapPea kernel), a few invariant computations, etc.
  • Fixed a little bug where KLO would try to do a meta-clasp-blowup on a non-embedded 2-gon when it's clicked on (which it shouldn't, and KLO would crash).
  • 0.93a on the Mac is a clean rebuild after updating my Mac build machine, MacOS, XCode, and Qt; Mac 0.921a showed some strange little user interface quirks (though it's the same code used on Windows) that I hope have been resolved. 
Please let me know of any issues with KLO if you find any (sending the recovered document after a crash makes it much easier to find the cause)!

Thursday, January 31, 2019

KLO 0.921a

KLO 0.921a is online at

Small fix so that KLO can read its files with band-slides and band-swims in them (thanks to Brendan Owens for pointing that out), plus changed the web link and gave one line of instructions when entering braids symbolically. 

Tuesday, January 29, 2019

KLO 0.92a

KLO 0.92 alpha is now online at
  • Bands can be drawn with knots (this is not new) to represent surfaces in 4-space; band-slides and band-swims for these diagrams have now been implemented:
    • To perform a band-slide, drag the end of the band to slide to an adjacent end from a different band.
    • To perform a band-swim, drag the end of the band to be swum along to an edge for a different band on the same face (note that this is effectively the opposite of the band-swim being done; starting with the band-end makes the interfacing simpler).
  • When constructing a new knot, a new checkbox now exists to specify a braid to close; selecting this opens up a dialog in which the number of strands and the braid can be entered (braid generators are a, b, c, ... from the top, with the inverses given by A, B, C, ...).  The braid is visually previewed as you enter it. 

Saturday, January 26, 2019

KLO 0.91a

Two new features of KLO have been introduced in KLO 0.91 alpha, along with one improvement:
  1. Relative Kirby diagrams (bottom components <bracketed>) are now possible, and a new button for exists for computer-aided turning upside-down of a Kirby diagram.  The initial steps are performed by KLO, after which the user manipulates the bracketed components into a zero-framed unlink (with the top components following along).  A button finishes the mode and reports the number of 3- and 4-handles.
  2. Kirby diagrams for 2-fold branched covers of knots and links are now a button-click away for any knot.
  • Blow-downs of ±1-framed 2-handles now only requires that there are no crossings inside the loop (crossings inside a loop with no self-crossings can still be cleared in one click by setting focus on the loop and clicking inside it).