larmm(3)

NAME
larmm - larmm: scale factor to avoid overflow, step in latrs

SYNOPSIS

  Functions
double precision function dlarmm (anorm, bnorm, cnorm)
DLARMM
real function slarmm (anorm, bnorm, cnorm)
SLARMM

Detailed Description

Function Documentation

  double precision function dlarmm (double precision anorm, double precision bnorm, double precision cnorm)

DLARMM

Purpose:

    !>
    !> DLARMM returns a factor s in (0, 1] such that the linear updates
    !>
    !>    (s * C) - A * (s * B)  and  (s * C) - (s * A) * B
    !>
    !> cannot overflow, where A, B, and C are matrices of conforming
    !> dimensions.
    !>
    !> This is an auxiliary routine so there is no argument checking.
    !>

Parameters
    ANORM

    !>          ANORM is DOUBLE PRECISION
    !>          The infinity norm of A. ANORM >= 0.
    !>          The number of rows of the matrix A.  M >= 0.
    !>

    BNORM

    !>          BNORM is DOUBLE PRECISION
    !>          The infinity norm of B. BNORM >= 0.
    !>

    CNORM

    !>          CNORM is DOUBLE PRECISION
    !>          The infinity norm of C. CNORM >= 0.
    !>

     References: C. C. Kjelgaard Mikkelsen and L. Karlsson, Blocked Algorithms for Robust Solution of Triangular Linear Systems. In: International Conference on Parallel Processing and Applied Mathematics, pages 68--78. Springer, 2017.

Definition at line 60 of file dlarmm.f.

  real function slarmm (real anorm, real bnorm, real cnorm)

SLARMM

Purpose:

    !>
    !> SLARMM returns a factor s in (0, 1] such that the linear updates
    !>
    !>    (s * C) - A * (s * B)  and  (s * C) - (s * A) * B
    !>
    !> cannot overflow, where A, B, and C are matrices of conforming
    !> dimensions.
    !>
    !> This is an auxiliary routine so there is no argument checking.
    !>

Parameters
    ANORM

    !>          ANORM is REAL
    !>          The infinity norm of A. ANORM >= 0.
    !>          The number of rows of the matrix A.  M >= 0.
    !>

    BNORM

    !>          BNORM is REAL
    !>          The infinity norm of B. BNORM >= 0.
    !>

    CNORM

    !>          CNORM is REAL
    !>          The infinity norm of C. CNORM >= 0.
    !>

     References: C. C. Kjelgaard Mikkelsen and L. Karlsson, Blocked Algorithms for Robust Solution of Triangular Linear Systems. In: International Conference on Parallel Processing and Applied Mathematics, pages 68--78. Springer, 2017.

Definition at line 60 of file slarmm.f.

Author

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