Introducing the Consortium for the Advancement of Scientific Software

Many of the scientific discoveries that shape society and contribute to continued technological advancement are supported by a sophisticated ecosystem of software technology (see Figure 1). “This software ecosystem has evolved over decades of research with input from countless stakeholders and application scientists,” Philip Carns of Argonne National Laboratory said. “Sustaining it and ensuring a strong foundation for the future requires a comprehensive and thoughtful approach to software stewardship and advancement.” During the 2025 SIAM Conference on Computational Science and Engineering, which is currently taking place in Fort Worth, Texas, Carns overviewed the Consortium for the Advancement of Scientific Software (CASS): a federation of member organizations that are dedicated to the stewardship and progression of scientific computing software.

As noted in its mission statement, CASS’ key values include stewardship and advancement in the context of the software ecosystem. “We’re not just trying to project current investments and sustain the current ecosystem,” Carns said. “We want to look at it as a comprehensive whole and be thoughtful about what we need to do to carry the software forward in the future,” Doing so will maintain U.S. competitiveness in scientific discovery.

The CASS software portfolio contains freely available libraries and tools that support cutting-edge computational science and engineering research on high-performance parallel computers. Most of the software—which is maintained by a variety of teams at academic institutions, government laboratories, and other agencies around the world—was developed with support from the U.S. Department of Energy’s (DOE) Office of Advanced Scientific Computing Research (ASCR) and Exascale Computing Project (ECP): a comprehensive research, development, and deployment program that sought to create the first capable exascale computing ecosystem in the U.S. “A lot of what we’re focusing on has been accelerated by the ECP,” Carns said.

The ECP, which ran from 2016 to 2024, provided funding for roughly 2,800 multidisciplinary individuals to generate exascale applications, software, and hardware. In 2022, with the initiative’s completion date rapidly approaching, the DOE solicited stewardship suggestions in the form of “seedling” proposals about how to best maintain the project’s innovative spirit. The following year, it asked a subset of these submissions to develop multiyear plans. And in 2024, the DOE offered initial awards that clarified the scope of the selected “software stewardship organizations” and mandated that they form a consortium to collaborate and coordinate activities. The CASS was formally established that summer.

This emphasis on collaboration drives much of the consortium’s efforts, as member organizations frequently pool resources for crosscutting activities like training, outreach, software delivery, and software best practice. “Members work together through the consortium to maximize the benefit for everyone,” Carns said. Because it operates on in-kind contributions of effort and other resources from member organizations, CASS has no budget of its own and no direct sponsors. However, all of the members have their own funding sources and gratefully acknowledge support from the ASCR via the Next Generation Scientific Software Technologies and Scientific Discovery through Advanced Computing programs.

New organizations can join at any time and do not require DOE sponsorship. Participating organizations are categorized as either core members—those who play an active role in consortium governance—or affiliate members, who uphold the mission but do not play an active governing role. CASS is governed by a member-appointed steering committee (see Figure 2). “This committee is very open,” Carns said. “We always welcome people to join the calls and hear what we’re up to.” Meanwhile, the CASS member organizations each have their own leadership, governance, and activities to fit their unique needs. 

The following six projects comprise CASS’ current core members:

• Center for Open-Source Research Software Stewardship and Advancement
• Frameworks, Algorithms, and Scalable Technologies for Mathematics
• Partnering for Scientific Software Ecosystem Opportunities 
• RAPIDS2: SciDAC Institute for Computer Science, Data, and Artificial Intelligence 
• Stewardship for Programming Systems and Tools
• Software Tools Ecosystem Project.

The Collaboration for Better Software (for Science) and Center for Sustaining Workflows and Application Services are affiliate members.

Carns concluded his presentation by encouraging attendees to engage with CASS by joining the mailing list to remain abreast of relevant news and events, contacting a member organization to learn more about their work, participating in a working group (most are open to the public), and considering future membership if they have a project that aligns with the consortium’s goals.