---
name: "dlarmm.f"
section: "3"
platform: "linux"
package: "lapack-doc"
version: "3.12.1-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/dlarmm.f"
---

# dlarmm.f(3)

## NAME

SRC/dlarmm.f

## SYNOPSIS

### Functions/Subroutines

double precision function **dlarmm** (anorm, bnorm, cnorm)\
 **DLARMM**

## Function/Subroutine 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**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.