109cc9507SBarry Smith--- 209cc9507SBarry Smithorphan: true 309cc9507SBarry Smith--- 409cc9507SBarry Smith 509cc9507SBarry Smith(2025_meeting)= 609cc9507SBarry Smith 709cc9507SBarry Smith# 2025 PETSc Annual Users Meeting and Tutorial 809cc9507SBarry Smith 994ff1df1SMatthew G. Knepley## Meeting location 1094ff1df1SMatthew G. Knepley 1113b80f9bSMatthew KnepleyMay 20-21, 2025, 101 Davis Hall, University of Buffalo, NY, USA ([105 White Rd, Amherst, NY 14260](https://maps.app.goo.gl/B38RsNe41Zd93rvX7)) 1209cc9507SBarry Smith 1309cc9507SBarry Smith## Meeting times 1409cc9507SBarry Smith 1594ff1df1SMatthew G. Knepley- Monday, May 19 - Tutorial (tutorials begin at 9am) 16ab026ea1SJunchao Zhang- Tuesday, May 20 - Meeting (begin at 9am) 17ab026ea1SJunchao Zhang- Wednesday, May 21 - Meeting (ends around 5pm) 1809cc9507SBarry Smith 195f0c5ebcSBarry Smith## Agenda 2094ff1df1SMatthew G. Knepley 2194ff1df1SMatthew G. Knepley[comment]: # (Intro: Python, Linear/Nonlinear Solver, GPU) 2294ff1df1SMatthew G. Knepley 2394ff1df1SMatthew G. Knepley[comment2]: # (Adv: Meshing, SNESVI, Optimization) 2494ff1df1SMatthew G. Knepley 2594ff1df1SMatthew G. Knepley### Monday, May 19: Tutorial 2694ff1df1SMatthew G. Knepley 2794ff1df1SMatthew G. Knepley| Time | Title | Speaker | 2894ff1df1SMatthew G. Knepley| -------- | ---------------------------------------------------------------------------------------------------------------------------- | ----------------------- | 2994ff1df1SMatthew G. Knepley| 9:00 am | Introduction | [Matt Knepley] | 3050177b3eSMatthew G. Knepley| 9:15 am | Tutorial I: Introductory PETSc | [Toby Isaac] | 3194ff1df1SMatthew G. Knepley| 12:00 pm | **Lunch** for tutorial attendees and early arrivees | | 328bc772e2SMatthew G. Knepley| 1:30 pm | Emergent flow asymmetries from the metachronal motion of the soft flexible paddles of the gossamer worm | [Alexander Hoover] | 3350177b3eSMatthew G. Knepley| 2:00 pm | Tutorial II: Advanced PETSc | [Matt Knepley and Toby Isaac] | 3494ff1df1SMatthew G. Knepley| 5:00 pm | End of first day | | 3594ff1df1SMatthew G. Knepley 3694ff1df1SMatthew G. Knepley### Tuesday, May 20: Scientific Program 3794ff1df1SMatthew G. Knepley 3894ff1df1SMatthew G. Knepley| Time | Title | Speaker | 3994ff1df1SMatthew G. Knepley| -------- | ---------------------------------------------------------------------------------------------------------------------------- | ----------------------- | 4094ff1df1SMatthew G. Knepley| 9:00 am | Meeting Introduction | [Matt Knepley] | 41*4c1aa3b1SMatthew G. Knepley| 9:05 am | A projection method for particle resampling | [Mark Adams](https://www.youtube.com/watch?v=vl5WOooGg_M&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=14&pp=iAQB) | 42*4c1aa3b1SMatthew G. Knepley| 9:30 am | Dense Broyden-Fletcher-Goldfarb-Shanno (BFGS) | [Hansol Suh](https://www.youtube.com/watch?v=efOjxXJeEXU&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=10&pp=iAQB) | 43*4c1aa3b1SMatthew G. Knepley| 10:00 am | IBAMR: Immersed-Boundary Adaptive Mesh Refinement | [David Wells](https://www.youtube.com/watch?v=-TYu8x8hkcU&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=9&pp=iAQB) | 44*4c1aa3b1SMatthew G. Knepley| 10:30 am | TaoTerm | [Toby Isaac](https://www.youtube.com/watch?v=XwEZ6-VqEt8&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=18&pp=iAQB) | 4594ff1df1SMatthew G. Knepley| 10:45 am | **Coffee Break** | | 46*4c1aa3b1SMatthew G. Knepley| 11:00 am | Multiple RHS multigrid for the lattice Dirac equation | [Peter Boyle](https://www.youtube.com/watch?v=eKks1IXHQ2E&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=17&pp=iAQB) | 47*4c1aa3b1SMatthew G. Knepley| 11:30 am | DMSwarmRT: Ray tracing with PETSc's particle management library DMSwarm | [Joseph Pusztay](https://www.youtube.com/watch?v=IrQ0ptBbzSU&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=11&pp=iAQB) | 48*4c1aa3b1SMatthew G. Knepley| 12:00 pm | Empire AI | [Matt Jones](https://www.youtube.com/watch?v=dHF2D2NIdgA&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=15&pp=iAQB) | 4994ff1df1SMatthew G. Knepley| 12:15 pm | **Lunch** | | 50*4c1aa3b1SMatthew G. Knepley| 1:30 pm | Exploring Quantum Phases of Interacting Lattice Models via Exact Diagonalization | [Cheng-Chien Chen](https://www.youtube.com/watch?v=MDYmajrhLsw&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=3&pp=iAQB) | 51*4c1aa3b1SMatthew G. Knepley| 2:00 pm | Cardiac Fluid Dynamics | [Boyce Griffith](https://www.youtube.com/watch?v=4T4sU4pmfEc&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=1&t=26s&pp=iAQB) | 52*4c1aa3b1SMatthew G. Knepley| 2:30 pm | Application of CutFEM and SCIFEM to the modeling of coastal processes through vegetation | [Chris Kees](https://www.youtube.com/watch?v=l-z2Hj9pGtY&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=4&pp=iAQB) | 53*4c1aa3b1SMatthew G. Knepley| 3:00 pm | PetscRegressor | [Richard Mills](https://www.youtube.com/watch?v=qto8TNTwkjw&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=5&pp=iAQB0gcJCfwJAYcqIYzv) | 5494ff1df1SMatthew G. Knepley| 3:15 pm | **Poster Session and Coffee Break** | | 5594ff1df1SMatthew G. Knepley| 4:30 pm | **End of Posters** | | 5694ff1df1SMatthew G. Knepley| 4:45 pm | Leave on bus for dinner at Niagara Falls | | 5794ff1df1SMatthew G. Knepley 5894ff1df1SMatthew G. Knepley 5994ff1df1SMatthew G. Knepley### Wednesday, May 21: Scientific Program 6094ff1df1SMatthew G. Knepley 6194ff1df1SMatthew G. Knepley| Time | Title | Speaker | 6294ff1df1SMatthew G. Knepley| -------- | ---------------------------------------------------------------------------------------------------------------------------- | ----------------------- | 63*4c1aa3b1SMatthew G. Knepley| 9:00 am | Mesh Transformations | [Matt Knepley](https://www.youtube.com/watch?v=s-83i-asJVQ&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=16&pp=iAQB) | 64*4c1aa3b1SMatthew G. Knepley| 9:30 am | Automatic Generation of Matrix-Free Routines for PDE Solvers with Devito via PETSc | [Zoe Leibowitz](https://www.youtube.com/watch?v=FAiuTPkowM0&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=19&pp=iAQB) | 65*4c1aa3b1SMatthew G. Knepley| 10:00 am | PetscFD: Simplifying PDE Solutions | [David Salac](https://www.youtube.com/watch?v=67gf2qQSWZQ&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=8&pp=iAQB) | 66*4c1aa3b1SMatthew G. Knepley| 10:30 am | Implications of nonlinear rheology for plate tectonics | [Margarete Jadamec](https://www.youtube.com/watch?v=ncq4VbNSn80&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=13&t=6s&pp=iAQB) | 6794ff1df1SMatthew G. Knepley| 10:45 am | **Coffee Break** | | 68*4c1aa3b1SMatthew G. Knepley| 11:00 am | Proteus Toolkit | [Darsh Nathawani](https://www.youtube.com/watch?v=16lIjuEhAOY&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=7&pp=iAQB) | 69*4c1aa3b1SMatthew G. Knepley| 11:30 pm | GitWorkflows | [Satish Balay](https://www.youtube.com/watch?v=MkNyrNuXImU&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=2&pp=iAQB) | 7050177b3eSMatthew G. Knepley| 12:00 pm | **Lunch** | | 71*4c1aa3b1SMatthew G. Knepley| 1:30 pm | pyop3: A DSL for Unstructured Mesh Stencil Calculations | [Conor Ward](https://www.youtube.com/watch?v=KdYDjjIL3xc&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=6&pp=iAQB) | 72f8116064SMatthew G. Knepley| 2:00 pm | IMEX in PETSc | [Hong Zhang] | 73*4c1aa3b1SMatthew G. Knepley| 2:15 pm | Early Experiences in Building AI Assistants for Improving the Productivity of PETSc Users and Developers | [Junchao Zhang, Hong Zhang](https://www.youtube.com/watch?v=4nj5XS95_GE&list=PLgFMPm27S9JrnzQmEZq54TGe5Iv8P6V_V&index=12&pp=iAQB) | 74f8116064SMatthew G. Knepley| 2:30 pm | **PETSc Roundtable** | | 7594ff1df1SMatthew G. Knepley| 3:30 pm | **Coffee Break** | | 7694ff1df1SMatthew G. Knepley| 3:45 pm | **PETSc Roundtable** | | 7794ff1df1SMatthew G. Knepley| 4:45 pm | Meeting Closes | | 7894ff1df1SMatthew G. Knepley 7994ff1df1SMatthew G. Knepley## List of Abstracts 8094ff1df1SMatthew G. Knepley 818bc772e2SMatthew G. Knepley(alexander-hoover)= 828bc772e2SMatthew G. Knepley 838bc772e2SMatthew G. Knepley:::{topic} **Emergent flow asymmetries from the metachronal motion of the soft flexible paddles of the gossamer worm** 848bc772e2SMatthew G. Knepley**Alexander Hoover** 858bc772e2SMatthew G. Knepley 868bc772e2SMatthew G. KnepleyCleveland State University 878bc772e2SMatthew G. Knepley 888bc772e2SMatthew G. KnepleyMetachronal waves are ubiquitous in propulsive and fluid transport systems across many different scales and morphologies in the biological world. Gossamer worms, or tomopterids, are a soft-bodied, holopelagic worm that use metachrony with their flexible, gelatinous parapodia to deftly navigate the midwater ocean column that they inhabit. In the following study, we develop a three-dimensional, fluid-structure interaction model, using the IBAMR and libmesh frameworks, of a tomopterid parapodium to explore the emergent metachronal waves formed from the interplay of passive body elasticity, active muscular tension, and hydrodynamic forces. After introducing our model, we examine the effects that varying material properties have on the stroke of an individual parapodium as well as the resulting fluid dynamics. We then explore the temporal dynamics when multiple parapodia are placed sequentially and how differences in the phase can alter the collective kinematics and resulting flow field. Finally, we examine the role of phase differences in a freely-swimming model. 898bc772e2SMatthew G. Knepley::: 908bc772e2SMatthew G. Knepley 918bc772e2SMatthew G. Knepley(mark-adams)= 928bc772e2SMatthew G. Knepley 938bc772e2SMatthew G. Knepley:::{topic} **A projection method for particle resampling** 948bc772e2SMatthew G. Knepley**Mark Adams** 958bc772e2SMatthew G. Knepley 968bc772e2SMatthew G. KnepleyLawrence Berkeley National Laboratory 978bc772e2SMatthew G. Knepley 988bc772e2SMatthew G. KnepleyParticle discretizations of partial differential equations are advantageous for high-dimensional kinetic models in phase space due to their better scalability than continuum approaches with respect to dimension. Complex processes collectively referred to as particle noise hamper long time simulations with particle methods. One approach to address this problem is particle mesh adaptivity or remapping, known as particle resampling. This talk introduces a resampling method that projects particles to and from a (finite element) function space. The method is simple; using standard sparse linear algebra and finite element techniques, it can adapt to almost any set of new particle locations and preserves all moments up to the order of polynomial represented exactly by the continuum function space. 998bc772e2SMatthew G. Knepley 1008bc772e2SMatthew G. KnepleyThis work is motivated by the Vlasov-Maxwell-Landau model of magnetized plasmas with up to six dimensions, 3X in physical space and 3V in velocity space, and is developed in the context of a 1X + 1V Vlasov-Poisson model of Landau damping with logically regular particle and continuum phase space grids. Stable long time dynamics are demonstrated up to T=500 and reproducibility artifacts and data with stable dynamics up to T=1000 are publicly available. 1018bc772e2SMatthew G. Knepley::: 1028bc772e2SMatthew G. Knepley 1038bc772e2SMatthew G. Knepley(hansol-suh)= 1048bc772e2SMatthew G. Knepley 1058bc772e2SMatthew G. Knepley:::{topic} **Dense Broyden-Fletcher-Goldfarb-Shanno (BFGS)** 1068bc772e2SMatthew G. Knepley**Hansol Suh** 1078bc772e2SMatthew G. Knepley 1088bc772e2SMatthew G. KnepleyArgonne National Laboratory 1098bc772e2SMatthew G. Knepley 1108bc772e2SMatthew G. KnepleyWe will present a new dense formulation of BFGS specialize for the Limited Memory-Variable Metric (KSPLMVM) linear solver in PETSc, and illustrate its use for optimization problems. 1118bc772e2SMatthew G. Knepley::: 1128bc772e2SMatthew G. Knepley 1138bc772e2SMatthew G. Knepley(david-wells)= 1148bc772e2SMatthew G. Knepley 1158bc772e2SMatthew G. Knepley:::{topic} **IBAMR: Immersed-Boundary Adaptive Mesh Refinement** 1168bc772e2SMatthew G. Knepley**David Wells** 1178bc772e2SMatthew G. Knepley 1188bc772e2SMatthew G. KnepleyUniversity of North Carolina, Chapel Hill 1198bc772e2SMatthew G. Knepley 1205f22b79aSDavid WellsIBAMR is a parallel implementation of the immersed boundary method and other relevant numerics, such as Navier-Stokes and multiphase flow solvers. This presentation showcases some applications built on IBAMR and describes how they are fundamentally powered by PETSc. 1218bc772e2SMatthew G. Knepley::: 1228bc772e2SMatthew G. Knepley 1238bc772e2SMatthew G. Knepley(joseph-pusztay)= 1248bc772e2SMatthew G. Knepley 1258bc772e2SMatthew G. Knepley:::{topic} **DMSwarmRT: Ray tracing with PETSc's particle management library DMSwarm** 1268bc772e2SMatthew G. Knepley**Joseph Pusztay** 1278bc772e2SMatthew G. Knepley 1288bc772e2SMatthew G. KnepleyUniversity at Buffalo 1298bc772e2SMatthew G. Knepley 1308bc772e2SMatthew G. KnepleyIn this talk I will present work with DMSwarm, PETSc's parallel particle management library, to construct a general purpose ray trace with applicability to ICF plasma. I will discuss underlying improvements to the DMSwarm API to better support device side computation of swarm operations to facilitate the ray trace, with initial scalability tests and results. Additionally, I will present and discuss light weight time stepping objects for device side computation of systems with large numbers of fields that may be stepped independently. 1318bc772e2SMatthew G. Knepley::: 1328bc772e2SMatthew G. Knepley 1338bc772e2SMatthew G. Knepley(cheng-chien-chen)= 1348bc772e2SMatthew G. Knepley 1358bc772e2SMatthew G. Knepley:::{topic} **Exploring Quantum Phases of Interacting Lattice Models via Exact Diagonalization** 1368bc772e2SMatthew G. Knepley**Cheng-Chien Chen** 1378bc772e2SMatthew G. Knepley 1388bc772e2SMatthew G. KnepleyUniversity of Alabama at Birmingham 1398bc772e2SMatthew G. Knepley 1408bc772e2SMatthew G. KnepleyFermionic particles cannot occupy the same quantum state due to the Pauli exclusion principle. Therefore, solving the quantum many-body Schrödinger equation for electrons on finite-size lattices is equivalent to solving a finite-dimensional eigenvalue problem, where the matrix dimension grows exponentially with the lattice size. Here, I will discuss the exact diagonalization technique for finding the low-energy eigenstates of interacting fermionic models on two-dimensional lattices. These interacting models are shown to host a variety of emergent quantum phases, such as superconductivity and antiferromagnetism. For a sparse matrix with 34 billion basis states, the underlying code based on PETSc/SLEPc achieves a strong scaling performance of 85% linear scaling on more than 100,000 CPUs. The presentation will conclude with a brief discussion of potential future research directions, including ultra-large-scale matrix diagonalization based on matrix-free algorithms and/or quantum circuit simulations. 1418bc772e2SMatthew G. Knepley::: 1428bc772e2SMatthew G. Knepley 1438bc772e2SMatthew G. Knepley(boyce-griffith)= 1448bc772e2SMatthew G. Knepley 1458bc772e2SMatthew G. Knepley:::{topic} **Cardiac Fluid Dynamics** 1468bc772e2SMatthew G. Knepley**Boyce Griffith** 1478bc772e2SMatthew G. Knepley 1488bc772e2SMatthew G. KnepleyUniversity of North Carolina, Chapel Hill 1498bc772e2SMatthew G. Knepley 1508bc772e2SMatthew G. KnepleyCardiac fluid dynamics fundamentally involves interactions between complex blood flows and the structural deformations of the muscular heart walls and the thin, flexible valve leaflets. I will initially focus on models of an in vitro pulse-duplicator system that is commonly used in the development and regulation of prosthetic heart valves. These models enable detailed comparisons between experimental data and computational model predictions but use highly simplified descriptions of cardiac anatomy and physiology. I will also present recent in vitro models, focusing on a new comprehensive model of the human heart. This heart model includes fully three-dimensional descriptions of all major cardiac structures along with biomechanics models that are parameterized using experimental tensile test data obtained exclusively from human tissue specimens. Simulation results demonstrate that the model generates physiological stroke volumes, pressure-volume loops, and valvular pressure-flow relationships, thereby illustrating is its potential for predicting cardiac function in both health and disease. Time permitting, I will end the talk by describing extensions of this model to incorporate a comprehensive description of cardiac electrophysiology and electro-mechanical coupling. 1518bc772e2SMatthew G. Knepley::: 1528bc772e2SMatthew G. Knepley 15350177b3eSMatthew G. Knepley(chris-kees)= 15450177b3eSMatthew G. Knepley 15550177b3eSMatthew G. Knepley:::{topic} **Application of CutFEM and SCIFEM to the modeling of coastal processes through vegetation** 15650177b3eSMatthew G. Knepley**Chris Kees** 15750177b3eSMatthew G. Knepley 15850177b3eSMatthew G. KnepleyLouisiana State University 15950177b3eSMatthew G. Knepley 16050177b3eSMatthew G. KnepleyUnderstanding the effects of sea level rise on coastal ecosystems involves complex solid materials, such as mixed sediments and vegetation. Physical flume and basin studies have long been used in coastal engineering to understand wave and current dynamics around such structures. Numerical flumes based on computational fluid dynamics and fluid-structure interaction have recently begun to augment physical models for design studies, particularly for engineered structures where established Arbitrary Lagrangian-Eulerian (ALE) methods based on boundary-conforming meshes and isoparametric or isogeoemtric finite element methods are effective. The rapid growth of lidar and photogrammetrytechniques at large scales and computed tomography at small scales has introduced the possibility of constructing numerical experiments for the complex natural materials in coastal ecosystems. These methods tend to produce low-order geometric representations with uneven resolution, which are typically not appropriate for conforming mesh generation. To address this challenge, recent work extended an existing ALE method to include embedded solid dynamics using a piecewise linear CutFEM approach. The implementation is based on equivalent polynomials. The approach retains the convergence properties of the CutFEM method while having a simple implementation within the existing twophase RANS model, which has been used frequently for numerical flume studies. This presentation will consider application and performance of the method for two critical coastal processes: wave interaction with vegetation and sediment dynamics. 16150177b3eSMatthew G. Knepley::: 16250177b3eSMatthew G. Knepley 16350177b3eSMatthew G. Knepley(matt-knepley)= 16450177b3eSMatthew G. Knepley 16550177b3eSMatthew G. Knepley:::{topic} **Mesh Transformations** 16650177b3eSMatthew G. Knepley**Matt Knepley** 16750177b3eSMatthew G. Knepley 16850177b3eSMatthew G. KnepleyUniversity at Buffalo 16950177b3eSMatthew G. Knepley 17050177b3eSMatthew G. KnepleyComputational meshes, as a way to partition space, form the basis of much of PDE simulation technology, for instance for the finite element and finite volume discretization methods. In complex simulations, we are often driven to modify an input mesh. For example, to refine, coarsen, extrude, change cell types, or filter it. This code can be voluminous, error-prone, spread over many special cases, and hard to understand and maintain by subsequent developers. We present a simple, table-driven paradigm for mesh transformation which can execute a large variety of transformations in a performant, parallel manner, along with experiments in the open source library PETSc which can be run by the reader. 17150177b3eSMatthew G. Knepley::: 17250177b3eSMatthew G. Knepley 1738bc772e2SMatthew G. Knepley(zoe-leibowitz)= 1748bc772e2SMatthew G. Knepley 1758bc772e2SMatthew G. Knepley:::{topic} **Automatic Generation of Matrix-Free Routines for PDE Solvers with Devito via PETSc** 1768bc772e2SMatthew G. Knepley**Zoe Leibowitz** 1778bc772e2SMatthew G. Knepley 1788bc772e2SMatthew G. KnepleyImperial College, London 1798bc772e2SMatthew G. Knepley 1808bc772e2SMatthew G. KnepleyTraditional numerical solvers are often optimized for specific hardware architectures, making their adaptation to new computing environments challenging. The rapid evolution of hardware increases the complexity of rewriting and re-optimizing these solvers. By combining domain-specific languages (DSLs) with automated code generation, the level of abstraction is raised, enabling the generation of high-performance code across diverse hardware architectures. Moreover, providing users with a high-level problem specification facilitates the development of complex PDE solvers in a form closer to continuous mathematics, reducing code complexity and maximizing reuse. 1818bc772e2SMatthew G. Knepley 1828bc772e2SMatthew G. KnepleyDevito, a DSL and compiler for finite-difference solvers, has been extended to integrate iterative solver functionality through an interface with PETSc, enabling the generation of solvers for various computational fluid dynamics (CFD) problems. As an industry-standard framework, Devito automates the generation of highly optimized explicit finite-difference kernels and stencil computations and has been extensively used in large-scale seismic inversion and medical imaging applications. The new developments introduce automatic generation of matrix-free routines in Devito, allowing interaction with PETSc’s suite of solvers. Key enhancements include support for iterative solvers, implicit time-stepping, coupled solvers, and matrix-free preconditioning. These features are fully integrated into Devito’s symbolic API while maintaining compatibility with staggered grids, subdomains, and custom stencils. 1838bc772e2SMatthew G. Knepley 1848bc772e2SMatthew G. KnepleyThis work expands Devito’s capabilities, enabling it to address a broader range of high-performance computing challenges, including incompressible flow problems in CFD. The new framework is demonstrated through benchmark simulations, including the backward-facing step and flow around a cylinder. 1858bc772e2SMatthew G. Knepley::: 1868bc772e2SMatthew G. Knepley 18750177b3eSMatthew G. Knepley(david-salac)= 1888bc772e2SMatthew G. Knepley 18950177b3eSMatthew G. Knepley:::{topic} **PetscFD: Simplifying PDE Solutions** 19050177b3eSMatthew G. Knepley**David Salac** 1918bc772e2SMatthew G. Knepley 1928bc772e2SMatthew G. KnepleyUniversity at Buffalo 1938bc772e2SMatthew G. Knepley 19450177b3eSMatthew G. KnepleyThis talk will outline recent efforts to include finite difference operations in PETSc through the addition of PetscFD. We begin by formally exploring the concept of stencil composition, showing that resulting stencil will have an accuracy equal to the lower of the two stencils being composed. The basic outline of PetscFD is then provided, in addition to several high-level functions that return matrices for arbitrary derivatives. Finally, the usage of PetscFD is demonstrated via several canonical examples. 1958bc772e2SMatthew G. Knepley::: 1968bc772e2SMatthew G. Knepley 19789f2ac7dSMatthew Knepley(margarete-jadamec)= 19889f2ac7dSMatthew Knepley 19989f2ac7dSMatthew Knepley:::{topic} **Implications of Rheology and Plate Geometry on Plate Tectonics** 20089f2ac7dSMatthew Knepley**Margarete Jadamec** 20189f2ac7dSMatthew Knepley 20289f2ac7dSMatthew KnepleyUniversity at Buffalo 20389f2ac7dSMatthew Knepley 20489f2ac7dSMatthew KnepleyPlate tectonic theory provides a self-consistent, first order explanation of the distribution of earthquakes, volcanoes, and mountain belts on Earth, thus forming a comprehensive framework for interpreting how internal processes are expressed at the Earth’s surface. Inherent in the tenet of plate tectonics is that the plates are internally rigid with deformation concentrated at the boundaries. However, adequately capturing the relevant physics that allows for both strong plate interiors and weak boundaries, and then numerically implementing the complex rheologies in software to model the time-dependent evolution of plate motion and subduction remains a challenge. A series of (a) two-dimensional models of generalized subduction and (b) three-dimensional, data-driven models of natural subduction are presented that examine how the subducting plate geometry, coupling along the subduction interface, and a non-linear mantle rheology control surface plate motion, viscous flow in the asthenosphere, and length-scales of decoupling between the plates and asthenosphere at convergent plate boundaries. The non-linear, visco-plastic rheology and complex subducted plate geometries require high-performance computing and optimized numerical solvers to resolve the flow dynamics. Results show the incorporation of a strain-rate dependent rheology allows for dynamic decoupling between the lithosphere and asthenosphere at subduction zones facilitating self-sustaining plate tectonics. In addition, the three-dimensional models produce dynamic upwelling off-axis from the subducted slab edge, suggesting a new mechanism to explain anomalous volcanism observed at lateral subduction zone terminations. 20589f2ac7dSMatthew Knepley::: 20689f2ac7dSMatthew Knepley 2078bc772e2SMatthew G. Knepley(conor-ward)= 2088bc772e2SMatthew G. Knepley 2098bc772e2SMatthew G. Knepley:::{topic} **pyop3: A DSL for Unstructured Mesh Stencil Calculations** 2108bc772e2SMatthew G. Knepley**Conor Ward** 2118bc772e2SMatthew G. Knepley 2128bc772e2SMatthew G. KnepleyImperial College, London 2138bc772e2SMatthew G. Knepley 2145f0c5ebcSBarry Smithpyop3 is a new domain-specific language that automates the application of local computational kernels over a mesh, termed 'unstructured mesh stencil calculations’. Such operations are ubiquitous across simulation methods including the finite element method and finite volume method, as well as preconditioners, slope limiters, and more. Written in Python, pyop3 takes advantage of some novel abstractions for describing mesh data (think generalised `PetscSection`) to describe complex mesh loops in a concise way that is agnostic to the underlying data layout. Having described the computation to be performed, pyop3 then uses just-in-time compilation to generate high-performance C code (CUDA/HIP coming soon) and coordinates its execution in parallel using MPI. 2158bc772e2SMatthew G. Knepley 2168bc772e2SMatthew G. Knepleypyop3 is built on top of PETSc, wrapping many of its data types, and the design of the new data layout abstractions are strongly influenced by DMPlex. 2178bc772e2SMatthew G. Knepley 2188bc772e2SMatthew G. KnepleyThis talk will introduce some of the novel abstractions that enable pyop3’s functionality before giving some examples of the sorts of computations that are expressible and the resulting code that is generated. 2198bc772e2SMatthew G. Knepley::: 2208bc772e2SMatthew G. Knepley 221a8b9febbSMatthew G. Knepley(darsh-nathawani)= 222a8b9febbSMatthew G. Knepley 223a8b9febbSMatthew G. Knepley:::{topic} **Proteus Toolkit** 224a8b9febbSMatthew G. Knepley**Darsh Nathawani** 225a8b9febbSMatthew G. Knepley 226a8b9febbSMatthew G. KnepleyLouisiana State University 227a8b9febbSMatthew G. Knepley 228a8b9febbSMatthew G. KnepleyProteus is a python package to solve PDEs using traditional and state-of-the-art numerical models. Proteus uses several C, C++ and Fortran libraries either as an external package or a part of Proteus. PETSc is a vital part of the development of Proteus. The objective of this talk is to introduce Proteus, explain how to get it and use it, and some initial performance tests using the Poisson problem and provide comparison with PETSc. This scaling analysis is a crucial part for a guidance to better design efficient algorithms. 229a8b9febbSMatthew G. Knepley::: 230a8b9febbSMatthew G. Knepley 23150177b3eSMatthew G. Knepley(tim-steinhoff)= 232a8b9febbSMatthew G. Knepley 23350177b3eSMatthew G. Knepley:::{topic} **Using PETSc in a Multi-application Environment** 23450177b3eSMatthew G. Knepley**Tim Steinhoff** 235a8b9febbSMatthew G. Knepley 23650177b3eSMatthew G. KnepleyGesellschaft für Anlagen- und Reaktorsicherheit (GRS) gGmbH 237a8b9febbSMatthew G. Knepley 23850177b3eSMatthew G. KnepleyIn this talk we provide an overview of the use of PETSc in the context of the code family AC<sup>2</sup> which is developed and distributed by GRS. AC<sup>2</sup> consists of multiple codes and is used to simulate the behavior of nuclear reactors during operation, transients, design basis and beyond design basis accidents up to radioactive releases to the environment. Access to PETSc is controlled by the self-developed wrapper NuT (Numerical Toolkit). We present a brief rundown of historical developments introducing NuT and therefore PETSc to handle certain numerical subtasks in AC<sup>2</sup>. This is accompanied by a deeper look into our latest development and the challenges that come with it in order to support the time evolution of nuclide inventories in burnup and decay calculations. 239a8b9febbSMatthew G. Knepley::: 240a8b9febbSMatthew G. Knepley 24194ff1df1SMatthew G. Knepley## Organizing Committees 24294ff1df1SMatthew G. Knepley 24394ff1df1SMatthew G. Knepley### Extramural Committee 24494ff1df1SMatthew G. Knepley- [Blaise Bourdin](https://math.mcmaster.ca/~bourdinb/) 24594ff1df1SMatthew G. Knepley- [Danny Finn](https://scholar.google.com/citations?user=l09jI6wAAAAJ&hl=en) 24694ff1df1SMatthew G. Knepley- [Toby Isaac](https://tisaac.gitlab.io/triquadtethex/) 24794ff1df1SMatthew G. Knepley- [Lois McInnes](https://wordpress.cels.anl.gov/curfman/) 24894ff1df1SMatthew G. Knepley- [Louis Moresi](https://www.moresi.info/) 24994ff1df1SMatthew G. Knepley- [Darsh Nathawani](https://darshnathawani.com/) 25094ff1df1SMatthew G. Knepley- [Barry Smith](https://barrysmith.github.io/) 25194ff1df1SMatthew G. Knepley- [Junchao Zhang](https://www.anl.gov/profile/junchao-zhang) 25294ff1df1SMatthew G. Knepley 25394ff1df1SMatthew G. Knepley### Local Committee 25494ff1df1SMatthew G. Knepley- [Margarete Jadamec](https://geovizlab.geology.buffalo.edu/) 25594ff1df1SMatthew G. Knepley- [Matt Jones](https://www.buffalo.edu/ccr/about-us/people/staff/jones.html) 25694ff1df1SMatthew G. Knepley- [Matt Knepley](https://cse.buffalo.edu/~knepley/) 25794ff1df1SMatthew G. Knepley- [Joseph Pusztay](https://www.linkedin.com/in/joseph-pusztay-174183129/) 25894ff1df1SMatthew G. Knepley- [David Salac](https://engineering.buffalo.edu/mechanical-aerospace/people/faculty/d-salac.html) 25994ff1df1SMatthew G. Knepley 2605f0c5ebcSBarry Smith## Sponsors 2615f0c5ebcSBarry Smith```{image} https://petsc.gitlab.io/annual-meetings/2025/Center-for-Computational-Research.png 2625f0c5ebcSBarry Smith:width: 400 2635f0c5ebcSBarry Smith``` 2645f0c5ebcSBarry Smith```{image} https://petsc.gitlab.io/annual-meetings/2025/Institute-for-Artificial-Intelligence-and-Data-Science-color.png 2655f0c5ebcSBarry Smith:width: 400 2665f0c5ebcSBarry Smith``` 2675f0c5ebcSBarry Smith 26809cc9507SBarry Smith## Questions and Meeting Discussion 26909cc9507SBarry Smith 27009cc9507SBarry SmithFor questions about the meeting contact <mailto:petsc2025@lists.mcs.anl.gov>. 271d5edbea4SSatish BalayJoin the discussion about the meeting at [PETSc on Discord](https://discord.gg/Fqm8r6Gcyb), [2025 PETSc Annual Users Meeting channel](https://discord.com/channels/1119324534303109172/1298348560600924200). 27294ff1df1SMatthew G. Knepley 27394ff1df1SMatthew G. Knepley## Code of Conduct 27494ff1df1SMatthew G. Knepley 27594ff1df1SMatthew G. KnepleyAll meeting attendees are expected to follow the PETSc/NumFocus Code of Conduct. The local committee will serve as the code of conduct response team, https://numfocus.org/code-of-conduct#response-team. Should any concerns arise during the meeting, please contact any response team member. 27694ff1df1SMatthew G. Knepley 2775f0c5ebcSBarry Smith 2785f0c5ebcSBarry Smith## Registration 2795f0c5ebcSBarry Smith 2805f0c5ebcSBarry SmithPlease [register](https://ti.to/nf-projects/petsc-annual-meeting) to save your seat. 2815f0c5ebcSBarry SmithFee: \$100, for breaks and lunches; free for students. 2825f0c5ebcSBarry Smith 2835f0c5ebcSBarry Smith## Submit a presentation 2845f0c5ebcSBarry Smith 2855f0c5ebcSBarry Smith[Submit an abstract](https://docs.google.com/forms/d/126KwzajoQvcqU_q7btNsYxFqbe7rJ_vASC-tejZfXDQ) to be included in the schedule. 2865f0c5ebcSBarry SmithWe welcome talks from all perspectives, including 2875f0c5ebcSBarry Smith 2885f0c5ebcSBarry Smith- contributions to PETSc 2895f0c5ebcSBarry Smith- use of PETSc in applications or libraries 2905f0c5ebcSBarry Smith- development of libraries and packages [called from PETSc](https://petsc.org/release/install/external_software/) 2915f0c5ebcSBarry Smith- just curious about using PETSc in applications 2925f0c5ebcSBarry Smith 2935f0c5ebcSBarry Smith## Student Travel Support 2945f0c5ebcSBarry Smith 2955f0c5ebcSBarry SmithWe have funding to provide travel support for students attending the meeting without their own funding. To apply, check the 2965f0c5ebcSBarry Smith"Student Funding Support" ticket while registering for the meeting. Early registration will increase your chance of obtaining travel support. 2975f0c5ebcSBarry Smith 2985f0c5ebcSBarry Smith## Suggested hotels 2995f0c5ebcSBarry Smith 3005f0c5ebcSBarry Smith- Hotels Near UB North 3015f0c5ebcSBarry Smith 3025f0c5ebcSBarry Smith - [Motel 6 Amherst, NY](https://www.motel6.com/en/home/property/buffalo-amherst.html) 4400 Maple Rd, Amherst, NY 14226, (716) 834-2231 3035f0c5ebcSBarry Smith - [Hampton Inn Buffalo - Amherst](https://www.hilton.com/en/hotels/bufcphx-hampton-buffalo-amherst/) 1601 Amherst Manor Dr, Amherst, NY 14221, (716) 559-7010 3045f0c5ebcSBarry Smith - [Candlewood Suites Buffalo Amherst](https://www.ihg.com/candlewood/hotels/us/en/amherst/bufcw/hoteldetail?cm_mmc=GoogleMaps-_-CW-_-US-_-BUFCW) 20 Flint Rd, Amherst, NY 14226, (716) 688-2100 3055f0c5ebcSBarry Smith - [DoubleTree by Hilton Hotel Buffalo-Amherst](https://www.hilton.com/en/hotels/buffldt-doubletree-buffalo-amherst/) 10 Flint Rd, Amherst, NY 14226, (716) 689-4414 3065f0c5ebcSBarry Smith - [Comfort Inn University](https://www.choicehotels.com/new-york/amherst/comfort-inn-hotels/ny293?mc=llgoxxpx) 1 Flint Rd, Amherst, NY 14226, (716) 415-1132 3075f0c5ebcSBarry Smith - [Fairfield Inn & Suites Buffalo Amherst/University](https://www.marriott.com/en-us/hotels/buffn-fairfield-inn-and-suites-buffalo-amherst-university/overview/?scid=f2ae0541-1279-4f24-b197-a979c79310b0) 3880 Rensch Rd, Amherst, NY 14228, (716) 204-8936 3085f0c5ebcSBarry Smith - [Staybridge Suites Buffalo-Amherst by IHG](https://www.ihg.com/staybridge/hotels/us/en/amherst/bufrr/hoteldetail?cm_mmc=GoogleMaps-_-SB-_-US-_-BUFRR}) 1290 Sweet Home Rd, Amherst, NY 14228, (716) 276-8750 3095f0c5ebcSBarry Smith 3105f0c5ebcSBarry Smith 3115f0c5ebcSBarry Smith- Hotels in Downtown Buffalo 3125f0c5ebcSBarry Smith 3135f0c5ebcSBarry Smith - [Holiday In Express & Suites Buffalo Downtown-Medical Ctr by IHG](https://www.ihg.com/holidayinnexpress/hotels/us/en/buffalo/bufms/hoteldetail?cm_mmc=GoogleMaps-_-EX-_-US-_-BUFMS) 601 Main St, Buffalo, NY 14203, (716) 854-5500, Located near a subway station 3145f0c5ebcSBarry Smith - [Hilton Garden Inn Buffalo Downtown](https://www.hilton.com/en/hotels/bufmsgi-hilton-garden-inn-buffalo-downtown/?SEO_id=GMB-AMER-GI-BUFMSGI&y_source=1_MjA4MTcyMy03MTUtbG9jYXRpb24ud2Vic2l0ZQ%3D%3D) 10 Lafayette Square, Buffalo, NY 14203, (716) 848-1000, Located near a subway station 3155f0c5ebcSBarry Smith - [Hampton Inn & Suites Buffalo Downtown](https://www.hilton.com/en/hotels/bufdthx-hampton-suites-buffalo-downtown/?SEO_id=GMB-AMER-HX-BUFDTHX&y_source=1_MjA4MzA5Ny03MTUtbG9jYXRpb24ud2Vic2l0ZQ%3D%3D) 220 Delaware Ave, Buffalo, NY 14202, (716) 855-2223, Located near Chippewa St/Nightlife 3165f0c5ebcSBarry Smith - [Embassy Suites by Hilton Buffalo](https://www.hilton.com/en/hotels/bufeses-embassy-suites-buffalo/?SEO_id=GMB-AMER-ES-BUFESES&y_source=1_MTEwOTkxNC03MTUtbG9jYXRpb24ud2Vic2l0ZQ%3D%3D) 200 Delaware Ave, Buffalo, NY 14202, (716) 842-1000, Located near Chippewa St/Nightlife 3175f0c5ebcSBarry Smith - [Curtiss Hotel](https://curtisshotel.com/) 210 Franklin St, Buffalo, NY 14202, (716) 954-4900, Located near Chippewa St/Nightlife 318