May 6, 2024: A message regarding other codes that have put TOPAS into their name


My name is Joseph Perl. I am the one and only software architect of TOPAS.  


A group has recently launched a separate project that incorporates the name TOPAS within their project name.  Let me say with absolute clarity that I have never been involved in that project, was not aware of that project until last week and will not be a part of that project.


If my work on TOPAS has been valuable in your work, I hope you will insist on clarity throughout our field of what intellectual property was already present in TOPAS versus what is created by others in any other project based on TOPAS.


As the one and only software architect of TOPAS from the start of the project until the present, I take pride in the following personal contributions to our field: I developed the overall TOPAS architecture, the TOPAS parameter control system, the TOPAS geometry design, TOPAS scoring design, TOPAS particle source system, TOPAS extensions framework, TOPAS 4D system, TOPAS multithreading system, and every other fundamental aspect of the TOPAS architecture. I developed the user engagement strategy, including user onboarding strategy and user forum. I maintained our GitHub. I built our automated testing system, and I painstakingly created all of the pre-built TOPAS versions, such that our users can work without ever having to learn about dependent libraries, compilers or linkers. My career has been focused on creating tools that are extraordinarily flexible, while also extraordinarily easy to use. If you found TOPAS to have those qualities, I hope you will see this as my contribution.


Please also help to discourage the notion that TOPAS is a closed-source project. TOPAS is open-source. Moving TOPAS to the most permissive style of open-source license was a change I led for the release of TOPAS 3.9. The process involved considerable work, as changes needed to be made to, for example, protect the integrity of non-open-source information that had been added to the code base over earlier years (many thanks to the bfg-repo-cleaner project for their invaluable tool). The change exposed the TOPAS community to the risk that all open-source projects face, of fragmentation and confusion. However, the change was important as it protected all users' ability to access the TOPAS code going forwards. To exploit that openness to create a new project whose name suggests the new project is the first open version of TOPAS is misleading.


The confusion recently caused by others may make it difficult for the non-profit TOPAS support organization, TOPAS MC Inc., to continue providing the level of support that users have appreciated in the past. 


I am proud to reflect that this organization, that I established in 2014, distributed TOPAS from its first public release through TOPAS 3.9 and grew the supported user community to today's level of 2773 users at 674 institutions in 70 countries.  Thank you again for making TOPAS a part of your work.


Joseph