https://robertcarson.org/tags/chai/Recent content in Chai on Robert CarsonHugo -- gohugo.ioen© 2026 Robert CarsonTue, 15 Apr 2025 00:00:00 +0000https://robertcarson.org/projects/snls/Tue, 15 Apr 2025 00:00:00 +0000https://robertcarson.org/projects/snls/<h2 class="relative group">Where It Started <div id="where-it-started" class="anchor"></div> <span class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none"> <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#where-it-started" aria-label="Anchor">#</a> </span> </h2> <p>SNLS predates both ExaCMech and ExaConstit. It was developed at LLNL specifically to solve the problem of running material model constitutive updates on the GPU, at a time when no existing nonlinear solver library was designed to do that. General-purpose solvers like MINPACK or PETSc are built for problems that live on the host. They carry significant overhead per call and are not structured for batched execution across millions of independent points simultaneously. In crystal plasticity specifically, every quadrature point in the mesh needs its own nonlinear solve to update stress and internal state at each time step, and those systems are dense, stiff, and need to run as fast as possible without any per-point failure being an option. That was the gap SNLS was built to fill.</p>