Developer Reference for Intel® oneAPI Math Kernel Library for Fortran
?la_gerpvgrw
Computes the reciprocal pivot growth factor norm(A)/norm(U) for a general matrix.
Syntax
call sla_gerpvgrw(n, ncols, a, lda, af, ldaf)
call dla_gerpvgrw(n, ncols, a, lda, af, ldaf)
call cla_gerpvgrw(n, ncols, a, lda, af, ldaf)
call zla_gerpvgrw(n, ncols, a, lda, af, ldaf)
Include Files
mkl.fi
Description
The ?la_gerpvgrw 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
- n
-
INTEGER. Specifies the order of the matrix A. The value of n must be at least zero.
ncols
INTEGER . The number of columns of the matrix A ; ncols ≥ 0.
a , af
REAL for sla_gerpvgrw
DOUBLE PRECISION for dla_gerpvgrw
COMPLEX for cla_gerpvgrw
DOUBLE COMPLEX for zla_gerpvgrw .
Arrays: a(lda,*) , af(ldaf,*) .
The array a contains the input n -by- n matrix A . The second dimension of a must be at least max(1,n) .
The array af contains the factors L and U from the factorization triangular factor L or U from the Cholesky factorization A = P*L*U as computed by ?getrf . The second dimension of af must be at least max(1,n) .
lda
INTEGER . The leading dimension of a ; lda≥ max(1,n) .
ldaf
INTEGER . The leading dimension of af ; ldaf≥ max(1,n) .