"Zhang, Junchao" <[email protected]> writes: > A side question: Do lossy compressors have value for PETSc?
Perhaps if they're very fast, but I think it's usually not PETSc's place to be performing such compression due to tolerances being really subtle. There certainly is a place for preconditioning using reduced precision. PETSc used to have MatScalar to store Mat entries in reduced (single) precision while MFFD Jacobian application and Krylov work stayed in double. That was used in FUN3D papers circa 2000 and was "successful", but rarely used in practice (PETSc had to be built a special way) and removed due to the maintenance burden. I think there would be interest in a runtime option to compress matrix entries. For regular stencil operations where they may be a lot of redundancy, such compression could be lossless. For general problems, simply working in reduced precision would be enough.
