Visible to Intel only — GUID: GUID-43252FE5-8956-4C55-ABD6-B12C27D52757
Visible to Intel only — GUID: GUID-43252FE5-8956-4C55-ABD6-B12C27D52757
?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. The number of linear equations, the order of the matrix A; n≥ 0. |
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). |