The corresponding paper is very interesting: https://arxiv.org/pdf/2010.03660.pdf https://arxiv.org/pdf/2010.03660.pdf Particularly the SpMV CS-1 code listing

The corresponding paper is very interesting: https://arxiv.org/pdf/2010.03660.pdf https://arxiv.org/pdf/2010.03660.pdf Particularly the SpMV CS-1 code listing on page 5, and this comment (in section VI.B) about accuracy: > The measured normwise relative residuals with mixed and 32-bit are shown in Figure 9. Up to iteration 7 the mixed precision implementation tracks the 32-bit, but then fails to reduce the residual further. With this precision, machine precision is about 10^−3. We have observed this accuracy for very well conditioned systems. Here, the growth of rounding errors during the iterative solve explains the loss of an additional factor of 10, leading to a plateau at a relative residual of 10^−2. We have not yet tested whether this accuracy is acceptable in the MFIX code. > We expect that for some realistic situations, mixed precision solvers are usable as is; in others they may need to be coupled with a correction scheme such as an iterative refinement or an outer iteration that solves a nonlinear system; and in other situations one may need to use higher precision arithmetic [MFIX is the NETL CFD described in the article] It feels a bit odd for the authors to declare the 200x speedup over fp64 runs on Joule, followed by "we don't know if these results at a lower precision are acceptable." very cool stuff regardless. 18 GB of SRAM on the same (very large) chip is insane.