[petsc-users] RAM usage by a sparse matrix

[Alexander Goncharov]

Hello PETSC developers!

I would like to ask a couple of questions about symmetric sparse matrix
storage

1. Is matrix frees unused preallocated nonzero space. For example, when
run with option -info, it says how many nonzeros were unused. Is this
unused space unallocated? 

2. How PETSC stores symmetric sparse matrices on a GPU? Does it stores
only half of it or not?
 
Thank you!

Alexander.