# larmm - Man Page

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

## 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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## Info

Tue Nov 28 2023 12:08:43 Version 3.12.0 LAPACK