> On Aug 4, 2017, at 2:52 PM, Xiangdong <[email protected]> wrote: > > Hello everyone, > > I have a quick questions on the MatMPIAIJSetPreallocation. If we do not pass > the exact number of nonzeros for o_nnz and d_nnz, (for example, > MAT_INFO_NZ_ALLOCATED is 50% more than MAT_INFO_NZ_USED), will the > performance of MatMult be affected? What effect will these allocated but > unused memory cause? It is not a big deal to have extra memory, it won't slow things down. If you under estimate it can slow things down a lot.
> > Thank you. > > Best, > Xiangdong
