Visible to Intel only — GUID: GUID-6F4EC43D-24CE-4C1E-88E5-754ACF85431C
Visible to Intel only — GUID: GUID-6F4EC43D-24CE-4C1E-88E5-754ACF85431C
?la_herpvgrw
Computes the reciprocal pivot growth factor norm(A)/norm(U) for a Hermitian indefinite matrix.
Syntax
call cla_herpvgrw( uplo, n, info, a, lda, af, ldaf, ipiv, work )
call zla_herpvgrw( uplo, n, info, a, lda, af, ldaf, ipiv, work )
Include Files
- mkl.fi
Description
The ?la_herpvgrw routine 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.
Input Parameters
uplo |
CHARACTER*1. Must be 'U' or 'L'. Specifies the triangle of A to store: If uplo = 'U', the upper triangle of A is stored, If uplo = 'L', the lower triangle of A is stored. |
n |
INTEGER. The number of linear equations, the order of the matrix A; n≥ 0. |
info |
INTEGER. The value of INFO returned from ?hetrf, that is, the pivot in column info is exactly 0. |
a, af |
COMPLEX for cla_herpvgrw DOUBLE COMPLEX for zla_herpvgrw. Arrays: a(lda,*), af(ldaf,*). a contains the n-by-n matrix A. The second dimension of a must be at least max(1,n). af contains the block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by ?hetrf. The second dimension of af must be at least max(1,n). |
lda |
INTEGER. The leading dimension of array a; lda≥max(1,n). |
ldaf |
INTEGER. The leading dimension of array af; ldaf≥max(1,n). |
ipiv |
INTEGER. Array, DIMENSIONn. Details of the interchanges and the block structure of D as determined by ?hetrf. |
work |
REAL for cla_herpvgrw DOUBLE PRECISION for zla_herpvgrw. Array, DIMENSION 2*n. Workspace. |