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larmm(3) LAPACK 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.

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.

Author

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Wed Feb 7 2024 11:30:40 Version 3.12.0