Minisymposium Presentation

Reducing the energy cost of computer simulations is critical. While numerical precision must be sufficient to yield reliable scientific insights, lower precision can significantly reduce energy consumption and computation time. We present Verificarlo (https://github.com/verificarlo/verificarlo), an open-source, LLVM-based framework for verifying and optimizing numerical accuracy in complex programs. Verificarlo integrates multiple floating-point backends that simulate numerical errors and the effects of lower precision arithmetic, including MCA / Stochastic Rounding. Before reducing precision, it is essential to ensure that simulations are numerically robust. Verificarlo employs alternative floating-point models to detect subtle numerical bugs and defines the number of significant digits probabilistically to assess computational accuracy. Its variable precision backend enables a thorough exploration of the trade-off between precision and performance, identifying code regions that can safely operate with smaller floating-point formats without compromising reproducibility. Verificarlo has been successfully applied in HPC applications such as neuroimaging pipelines, DFT quantum mechanical modeling, and structure simulations.