Developer Reference for Intel® oneAPI Math Kernel Library for Fortran
?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. Specifies the order of the matrix A. The value of n must be at least zero.
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, DIMENSION n . 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.