SLA_PORPVGRW
Purpose
SLA_PORPVGRW computes the reciprocal pivot growth factor
norm(A)/norm(U). The "max absolute element" norm is used. If this is
much less than 1, the stability of the LU factorization of the
(equilibrated) matrix A could be poor. This also means that the
solution X, estimated condition numbers, and error bounds could be
unreliable.
norm(A)/norm(U). The "max absolute element" norm is used. If this is
much less than 1, the stability of the LU factorization of the
(equilibrated) matrix A could be poor. This also means that the
solution X, estimated condition numbers, and error bounds could be
unreliable.
Arguments
| UPLO |
(input) CHARACTER*1
= 'U': Upper triangle of A is stored;
= 'L': Lower triangle of A is stored. |
| NCOLS |
(input) INTEGER
The number of columns of the matrix A. NCOLS >= 0.
|
| A |
(input) REAL array, dimension (LDA,N)
On entry, the N-by-N matrix A.
|
| LDA |
(input) INTEGER
The leading dimension of the array A. LDA >= max(1,N).
|
| AF |
(input) REAL array, dimension (LDAF,N)
The triangular factor U or L from the Cholesky factorization
|
| A |
= U**T*U or A = L*L**T, as computed by SPOTRF.
|
| LDAF |
(input) INTEGER
The leading dimension of the array AF. LDAF >= max(1,N).
|
| WORK |
(input) REAL array, dimension (2*N)
|