1. Set the scene (5 minutes)
2. The Posthoc project (5 minutes)
3. Live demos (5 minutes)
4. What's next (5 minutes)

Find the slides here

https://pathfinding.ai/posthoc-icaps25/

"Spontaneous brilliance"

Visualisation for search

InLPG Link

(Gereveni and Saetti, 2008)

Web Planner Link

(Magnaguagno et al., 2017)

MovingAI Lab Demos Link

(Sturtevant, 2020)

MAES Link

(Andreason et al., 2022)

How about visualisations for my algorithm?

Search problems and algorithms come in all shapes and sizes.

• Various domains
• Various algorithms and procedures
• Different programming languages
• We want to see different things

PlanViz Link
(Chan et al., 2024)

Existing problem solving methods we see

• Use one of the visualisers
• Logs
• Debuggers
• DIY from scratch
• Trial and error
• Matplotlib hacks
• Just think harder

What can we do incorporate visualisation into everyday problem solving?

• Framework that makes a minimal set of powerful assumptions
• Way to record program behaviour
• Way to quickly DIY visualisations

Also

• Language agnostic

The Posthoc project

https://posthoc.pathfinding.ai/

Setting expectations

• Simple but effective visualisations
• Not trying to replace any tools

Two parts

• Search trace format
• Posthoc visualiser

1. Search trace

• Textual recording of your algorithmic procedure
• Optional description of the visualisation model

Why YAML?

• Standing on shoulder of giant
• Super easy to read and write (for people and programs)

Producing search traces

• Just print() / cout << / System.out.println()
• Solvers can generate them e.g. --log
• Write small examples by hand

2. Posthoc visualiser

• Separate from the search trace
• Toolbox/visualisation suite for search traces
• Replay and interactive inspection
• Tree and graph visualisations
• Custom visualisations
• Breakpoints for debugging,
• etc.

Live demo

• Creating search traces
• Posthoc quickstart
• Tree and graph visualisations
• How custom visualisations work
• Playback and inspection

Follow along:
https://pathfinding.ai/news/using-posthoc-with-piglet/

Posthoc:
https://posthoc.pathfinding.ai/

What's next

Making search visualisations accessible

Towards interoperable visualisations

@solver developers

• Requires solver support
• Let your algorithmic procedures be visualisable via search traces
• Generate logs in the search trace format

@tools developers

• Tools that take in the search trace for analysis

Making progress in search and planning discoverable

• A place to store, share, and publish visualisations
• Let the community discover your work

The future for the Posthoc visualiser

• Extension marketplace
• Component libraries (higher-order components)
• Renderers (3D, point cloud, splatting)
• Direct solver/visualiser interactivity (automatically pull in search traces)
• Many in-development and planned features
• 34 open issues
• Star us on GitHub: https://github.com/shortestpathlab/posthoc-app