The parallel selected inversion routine for a real symmetric matrix can be used as follows. This assumes that the size of MPI_COMM_WORLD
is nprow * npcol
.
This routine computes the selected elements of the matrix \(A^{-1}=(H - z S)^{-1}\) in parallel. The input matrix \(H\) follows the Distributed compressed sparse column (CSC) format , defined through the variables colptrLocal
, rowindLocal
, HnzvalLocal
. The input matrix \(S\) can be omitted if it is an identity matrix and by setting isSIdentity=1
. If \(S\) is not an identity matrix, the nonzero sparsity pattern is assumed to be the same as the nonzero sparsity pattern of \(H\). Both HnzvalLocal
and SnzvalLocal
are double precision arrays.
An example is given in driver_pselinv_real.c, which evaluates the selected elements of the inverse of the matrix saved in examples/lap2dr.matrix
. See also PPEXSISelInvRealSymmetricMatrix for detailed information of its usage.