> Broadly, you have two options: > - You generate the matrix only at the root process. This may make your code simpler, e.g. implementing writing the matrix to a file is trivial (writing does not have to be done in parallel), but your other processes will be sitting idle until you finished generating the matrices. > > - You can generate parts of the matrix in different processes. You may have to design your program more carefully, but your worker processes won't be sitting idle while a single process generates the matrix.