LA_GERPVGRW - 5.2 English - 68552

AOCL API Guide (68552)

Document ID
68552
Release Date
2025-12-29
Version
5.2 English
template<typename T>
T la_gerpvgrw(integer *n, integer *ncols, T *a, integer *lda, T *af, integer *ldaf)#

LA_GERPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U)

Purpose:

 LA_GERPVGRW 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.
Parameters:
  • N[in]

    N is INTEGER

    The number of linear equations, i.e., the order of the matrix A. N >= 0.

  • NCOLS[in]

    NCOLS is INTEGER

    The number of columns of the matrix A. NCOLS >= 0.

  • A[in]

    A is REAL array, dimension (LDA,N)

    On entry, the N-by-N matrix A.

  • LDA[in]

    LDA is INTEGER

    The leading dimension of the array A. LDA >= fla_max(1,N).

  • AF[in]

    AF is REAL array, dimension (LDAF,N)

    The factors L and U from the factorization A = P*L*U as computed by SGETRF.

  • LDAF[in]

    LDAF is INTEGER

    The leading dimension of the array AF. LDAF >= fla_max(1,N).