LAQGB - 5.2 English - 68552

AOCL API Guide (68552)

Document ID
68552
Release Date
2025-12-29
Version
5.2 English
template<typename T>
void laqgb(integer *m, integer *n, integer *kl, integer *ku, T *ab, integer *ldab, T *r, T *c, T *rowcnd, T *colcnd, T *amax, char *equed)#

LAQGB scales a general band matrix, using row and column scaling factors computed by gbequ.

Purpose:

   LAQGB equilibrates a general M by N band matrix A with KL
   subdiagonals and KU superdiagonals using the row and scaling factors
   in the vectors R and C.
Parameters:
  • M[in]

    M is INTEGER

    The number of rows of the matrix A. M >= 0.

  • N[in]

    N is INTEGER

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

  • KL[in]

    KL is INTEGER

    The number of subdiagonals within the band of A. KL >= 0.

  • KU[in]

    KU is INTEGER

    The number of superdiagonals within the band of A. KU >= 0.

  • AB[inout]

    AB is REAL array, dimension (LDAB,N)

    On entry, the matrix A in band storage, in rows 1 to KL+KU+1. The j-th column of A is stored in the j-th column of the array AB as follows: AB(ku+1+i-j,j) = A(i,j) for fla_max(1,j-ku)<=i<=min(m,j+kl)

    On exit, the equilibrated matrix, in the same storage format as A. See EQUED for the form of the equilibrated matrix.
  • LDAB[in]

    LDAB is INTEGER

    The leading dimension of the array AB. LDA >= KL+KU+1.

  • R[in]

    R is REAL array, dimension (M)

    The row scale factors for A.

  • C[in]

    C is REAL array, dimension (N)

    The column scale factors for A.

  • ROWCND[in]

    ROWCND is REAL

    Ratio of the smallest R(i) to the largest R(i).

  • COLCND[in]

    COLCND is REAL

    Ratio of the smallest C(i) to the largest C(i).

  • AMAX[in]

    AMAX is REAL

    Absolute value of largest matrix entry.

  • EQUED[out]

    EQUED is CHARACTER*1

    Specifies the form of equilibration that was done.

    = ‘N’: No equilibration

    = ‘R’: Row equilibration, i.e., A has been premultiplied by diag(R).

    = ‘C’: Column equilibration, i.e., A has been postmultiplied by diag(C).

    = ‘B’: Both row and column equilibration, i.e., A has been replaced by diag(R) * A * diag(C).

template<typename T, typename Ta>
void laqgb(integer *m, integer *n, integer *kl, integer *ku, T *ab, integer *ldab, Ta *r, Ta *c, Ta *rowcnd, Ta *colcnd, Ta *amax, char *equed)#