[petsc-users] Tips on integrating MPI ksp petsc into my application?

[Barry Smith]

  If you use MatLoad() it never has the entire matrix on a single rank at the same time; it efficiently gets the matrix from the file spread out over all the ranks. 

> On Dec 6, 2021, at 11:04 PM, Faraz Hussain via petsc-users <petsc-users at mcs.anl.gov> wrote:
> 
> I am studying the examples but it seems all ranks read the full matrix. Is there an MPI example where only rank 0 reads the matrix? 
> 
> I don't want all ranks to read my input matrix and consume a lot of memory allocating data for the arrays. 
> 
> I have worked with Intel's cluster sparse solver and their documentation states:
> 
> " Most of the input parameters must be set on the master MPI process only, and ignored on other processes. Other MPI processes get all required data from the master MPI process using the MPI communicator, comm. "