Trilinos is a community-developed, open-source software framework that facilitates building large-scale, complex, multiscale, multiphysics simulation code bases for scientific and engineering problems. Since the Trilinos framework has undergone substantial changes to support new applications and new hardware architectures, this document is an update to “An Overview of the Trilinos project” by Heroux et al. (ACM Transactions on Mathematical Software, 31(3):397–423, 2005). It describes the design of Trilinos, introduces its new organization in product areas, and highlights established and new features available in Trilinos. Particular focus is put on the modernized software stack based on the Kokkos ecosystem to deliver performance portability across heterogeneous hardware architectures. This article also outlines the organization of the Trilinos community and the contribution model to help onboard interested users and contributors.

This paper describes objective technical results and analysis.Any subjective views or opinions that might be expressed

“BLIS: A Framework for Rapidly Instantiating BLAS Functionality” by Field G. Van Zee and Robert A. van de Geijn (see: http://dx.doi.org/10.1145/2764454 ) includes single-platform BLIS performance results for both level-2 and level-3 operations that is competitive with OpenBLAS, ATLAS, and Intel MKL. A detailed description of the configuration used to generate the performance results was provided to the reviewer by the authors. All the software components used in the comparison were reinstalled and new performance results were generated and compared to the original results. After completing this process, the published results are deemed replicable by the reviewer.

Software lifecycles are becoming an increasingly important issue for computational science & engineering (CSE) software. The process by which a piece of CSE software begins life as a set of research requirements and then matures into a trusted high-quality capability is both commonplace and extremely challenging. Although an implicit lifecycle is obviously being used in any effort, the challenges of this process-respecting the competing needs of research vs. production-cannot be overstated. Here we describe a proposal for a well-defined software life-cycle process based on modern Lean/Agile software engineering principles. What we propose is appropriate for many CSE software projects that are initially heavily focused on research but also are expected to eventually produce usable high-quality capabilities. The model is related to TriBITS, a build, integration and testing system, which serves as a strong foundation for this lifecycle model, and aspects of this lifecycle model are ingrained in the TriBITS system. Indeed this lifecycle process, if followed, will enable large-scale sustainable integration of many complex CSE software efforts across several institutions.

Scientific and engineering programming has been around since the beginning of computing, often being the driving force for new system development and innovation. At the same time a continual focus on new modeling capabilities, and some apparent cultural issues, find software processes for many computational science and engineering (CSE) software projects lacking. Certainly there are notable exceptions, but our experience has been that CSE software projects, although committed to writing high-quality software, have few if any formal software processes and tools in place, and are often unaware of formal software quality assurance (SQA) concepts. Presently, increasing complexity of applications and a broad push to certify computations are dictating a higher standard for CSE software quality; it is no longer sufficient to claim to write high quality software. However, traditional software development models can be impractical for CSE projects to implement. Despite this, CSE software teams can benefit by implementing valuable SQA processes and tools. In this paper we outline some the processes and tools that are successfully used by the Trilinos Project. These tools and processes have been useful not only in increasing verifiable software quality, but also have improved overall software quality, and the development experience in general

The Trilinos Project is an effort to facilitate the design, development, integration, and ongoing support of mathematical software libraries within an object-oriented framework for the solution of large-scale, complex multiphysics engineering and scientific problems. Trilinos addresses two fundamental issues of developing software for these problems: (i) providing a streamlined process and set of tools for development of new algorithmic implementations and (ii) promoting interoperability of independently developed software.Trilinos uses a two-level software structure designed around collections of packages . A Trilinos package is an integral unit usually developed by a small team of experts in a particular algorithms area such as algebraic preconditioners, nonlinear solvers, etc. Packages exist underneath the Trilinos top level, which provides a common look-and-feel, including configuration, documentation, licensing, and bug-tracking.Here we present the overall Trilinos design, describing our use of abstract interfaces and default concrete implementations. We discuss the services that Trilinos provides to a prospective package and how these services are used by various packages. We also illustrate how packages can be combined to rapidly develop new algorithms. Finally, we discuss how Trilinos facilitates high-quality software engineering practices that are increasingly required from simulation software.