Developer Reference for Intel® oneAPI Math Kernel Library for Fortran
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?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.  |