HP MLIB User's Guide Vol. 2 7th Ed.

770 HP MLIB LAPACK User’s Guide
pdgsrfs_ABXglobal/pzgsrfs_ABXglobal Improve the computed solutions to systems of linear
equations
LUstruct
(input)
The distributed data structures storing L and U
factors. The L and U factors are obtained from pdgstrf
or pzgstrf for the possibly scaled and permuted matrix
A.
grid
(input)
The 2D process mesh. It contains the MPI
communicator, the number of process rows (NPROW),
the number of process columns (NPCOL), and my
process rank, It is an input argument to all the parallel
routines.
B
(input)
(global) The N-by-NRHS right-hand side matrix of the possibly
equilibrated and row permuted system.
NOTE B must reside on all processes.
ldb
(input)(global)
The leading dimension of matrix B.
X
(input/output)
(global)
On entry, the solution matrix X, as computed by
pdgstrs_Bglobal or pzgstrs_Bglobal. On exit, the
improved solution matrix X. If DiagScale=COL or
BOTH, X should be premultiplied by diag(C) in order to
obtain the solution to the original system.
NOTE X must reside on all processes.
ldx
(input)(global)
The leading dimension of matrix X.
nrhs
(input)
The number of right-hand sides.
berr
(output)
The vector with dimension nrhs containing the
componentwise relative backward error of each
solution vector X(j) (i.e., the smallest relative change in