# History of the Boost Graph Library

The Boost Graph Library began its life as the Generic Graph Component Library (GGCL), a software project at the Lab for Scientific Computing (LSC) at the University of Notre Dame, under the direction of Professor Andrew Lumsdaine. The Lab's research directions include numerical linear algebra, parallel computing, and software engineering (including generic programming).

Soon after the Standard Template Library was released, work began at the LSC to apply generic programming to scientific computing. The Matrix Template Library (Jeremy Siek's masters thesis) was one of the first projects. Many of the lessons learned during construction of the MTL were applied to the design and implementation of the GGCL.

Graph algorithms play an important role in sparse matrix computations, so the LSC had a need for a good graph library. However, none of the available graph libraries (LEDA, GTL, Stanford GraphBase) were written using the generic programming style of the STL, and hence did not fulfill the flexibility and high-performance requirements of the LSC. Others were also expressing interest in a generic C++ graph library. During a meeting with Bjarne Stroustrup we were introduced to several people at AT\&T who needed such a library. There had also been earlier work in the area of generic graph algorithms, including some codes written by Alexander Stepanov, and Dietmar Kühl's masters thesis.

With this in mind, and motivated by homework assignments in his algorithms class, Jeremy began prototyping an interface and some graph classes in the spring on 1998. Lie-Quan Lee then developed the first version of GGCL, which became his masters thesis project.

The following year, Jeremy went to work for SGI with Alexander Stepanov and Matt Austern. During this time Alex's disjoint-sets based connected components algorithm was added to GGCL, and Jeremy began working on the concept documentation for GGCL similar to Matt's STL documentation.

While working at SGI, Jeremy heard about Boost and was excited to find a group of people interested in creating high-quality C++ libraries. At boost there were several people interested in generic graph algorithms, most notably Dietmar Kühl. Some discussions about generic interfaces for graph structures resulted in the a revision of GGCL which closely resembles the current Boost Graph Library interface.

On September 4, 2000 GGCL passed the Boost formal review and became the Boost Graph Library (BGL). The first release of BGL was September 27, 2000.

## Changes by version

- Version 1.34.0
  New algorithms and components
  - `edmonds_maximum_cardinality_matching`, from Aaron Windsor.
  - `lengauer_tarjan_dominator_tree`, from JongSoo Park.
  - `compressed_sparse_row_graph`, from Jeremiah Willcock and Douglas Gregor of Indiana University.
  - `sorted_erdos_renyi_iterator`, from Jeremiah Willcock of Indiana University.
  Enhancements
  - Note: the name of the compiled library for GraphViz reading is now called `boost_graph` rather than `bgl-viz`.
  - `biconnected_components` now has a visitor parameter and supports named parameters, from Janusz Piwowarski.
  - `adjacency_matrix` now models the Bidirectional Graph concept.
  - `adjacency_list` is now Serializable, from Jeremy Siek of Rice University.
  - Added `edges_size_type` and `vertices_size_type` to `adjacency_list_traits`, from Jeremy Siek of Rice University.
  - Added `operator<` , etc. to the edge descriptor of `adjacency_list`, from Jeremy Siek of Rice University.
  Bug Fixes
  - Fixed a bug that causes the relaxed heap to fail on x86 Linux.
  - Bundled properties now work with adjacency list I/O.
  - `floyd_warshall_all_pairs_shortest_paths` now properly uses its `compare`, `inf`, and `zero` parameters.
  - `johnson_all_pairs_shortest_paths` now supports `compare`, `combine`, `inf`, and `zero`.
  - Fixed a bug in smallest_last_vertex_ordering.hpp which could cause a vertex to be moved to the wrong bucket during an BucketSorter update.
- Version 1.33.1
  Bug Fixes
  - `fruchterman_reingold_force_directed_layout`: Fixed enumeration of grid-force pairs, which caused some odd graph formations along grid lines.
  - `king_ordering` and `cuthill_mckee_ordering`: Fixed bug that caused failures with the multi-component version of these algorithms.
- Version 1.33.0
  New algorithms and components
  - Experimental Python bindings, from Doug Gregor and Indiana University.
  - `floyd_warshall_all_pairs_shortest_paths`, from Lauren Foutz and Scott Hill.
  - `astar_search`, from Kristopher Beevers and Jufeng Peng.
  - `fruchterman_reingold_force_directed_layout`, from Doug Gregor and Indiana University.

- `biconnected_components` and `articulation_points`, from Indiana University.
- `gursoy_atun_layout`, from Jeremiah Willcock and Doug Gregor of Indiana University.
- `king_ordering`, from D. Kevin McGrath of Indiana University.
- `erdos_renyi_iterator`
- `plod_iterator`
- `small_world_iterator`
Enhancements

- `bellman_ford_shortest_paths` now permits one to specify the starting vertex, so that it will perform its own initialization.
- `undirected_dfs` is now data-recursive, resulting in improved performance in some cases, from Synge Todo.
- `dijkstra_shortest_paths` now uses a relaxed heap [61] as its priority queue, improving its complexity to O(V log V) and improving real-world performance for larger graphs.
- `read_graphviz` now has a new, Spirit-based parser that works for all graph types and supports arbitrary properties on the graph, from Ron Garcia. The old, Bison-based GraphViz reader has been deprecated and will be removed in a future Boost release.
- `write_graphviz` now supports output of dynamic properties (as read in through the new `read_graphviz`).
- `cuthill_mckee_ordering` has been recast as an invocation of `breadth_first_search` and now supports graphs with multiple components.
- `subgraph` now supports bundled properties. `get_property` now refers to the subgraph property, not the root graph's property.
- `filtered_graph` now supports bundled properties.
- `reverse_graph` now supports bundled properties, `set_property`, and `get_property`.

Bug fixes

- `bellman_ford_shortest_paths` now deals with unreachable vertices better.
- `adjacency_list`: parallel edge removal with `OutEdgeListS = listS` has been fixed. Copying and swapping has been fixed.
- Incremental connected components: fixed a bug in the `incremental_components` routine that may have caused incorrect results.
- The `remove_out_edge_if` function for an undirected `adjacency_list` has been rewritten and should no longer dereference singular iterators.
- `write_graphviz` now accepts a `vertex_id` parameter that is used to name the nodes.
- `read_graphviz` now accepts empty attribute lists.
- `sequential_vertex_coloring` has been updated, tested, and documented.

Copyright © 2000-2001 | Jeremy Siek, Indiana University (jsiek@osl.iu.edu) Lie-Quan Lee, Indiana University (llee@cs.indiana.edu) Andrew Lumsdaine, Indiana University (lums@osl.iu.edu)