# MATIS

MATIS = "is" - A matrix type to be used for using the Neumann-Neumann type preconditioners. This stores the matrices in globally unassembled form. Each processor assembles only its local Neumann problem and the parallel matrix vector product is handled "implicitly".
### Operations Provided

### Options Database Keys

Notes: Options prefix for the inner matrix are given by -is_mat_xxx

You must call MatSetLocalToGlobalMapping() before using this matrix type.

You can do matrix preallocation on the local matrix after you obtain it with
MatISGetLocalMat()

### See Also

PC, MatISGetLocalMat(), MatSetLocalToGlobalMapping()

**Level:**advanced

Location:src/mat/impls/is/matis.c

Index of all Mat routines

Table of Contents for all manual pages

Index of all manual pages