---
title: "SHOP: Simple Hierarchical Ordered Planner"
authors:
  - "Dana S. Nau"
  - "Yue Cao"
  - "Amnon Lotem"
  - "Héctor Muñoz-Avila"
doi: ""
url: "https://ijcai.org/proceedings/1999/138"
pdf: "https://ijcai.org/proceedings/1999/0138.pdf"
venue: "Proceedings of the Sixteenth International Joint Conference on Artificial Intelligence"
year: 1999
pages: "968-974"
track: "Planning and Scheduling"
keywords:
---

# SHOP: Simple Hierarchical Ordered Planner

Dana S. Nau, Yue Cao, Amnon Lotem, Héctor Muñoz-Avila

*Proceedings of the Sixteenth International Joint Conference on Artificial Intelligence*, pages 968-974.

## Abstract

SHOP (Simple Hierarchical Ordered Planner) is a domain-independent HTN planning system with the following characteristics. • SHOP plans for tasks in the same order that they will later be executed. This avoids some goalinteraction issues that arise in other HTN planners, so that the planning algorithm is relatively simple. • Since SHOP knows the complete world-state at each step of the planning process, it can use highly expressive domain representations. For example, it can do planning problems that require complex numeric computations. • In our tests, SHOP was several orders of magnitude faster than Blackbox and several times faster than TLplan, even though SHOP is coded in Lisp and the other planners are coded in C.