---
name: "isamax"
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/isamax.f"
---

# isamax(3)

Part of [isamax.f(3)](/isamax.f/3.md).

## NAME

BLAS/SRC/isamax.f

## SYNOPSIS

### Functions/Subroutines

integer function **isamax** (n, sx, incx)\
 **ISAMAX**

## Function/Subroutine Documentation

### integer function isamax (integer n, real, dimension(\*) sx, integer incx)

**ISAMAX**

**Purpose:**

```
!>
!>    ISAMAX finds the index of the first element having maximum absolute value.
!>
```

**Parameters**

*N*

```
!>          N is INTEGER
!>         number of elements in input vector(s)
!>
```

*SX*

```
!>          SX is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
!>
```

*INCX*

```
!>          INCX is INTEGER
!>         storage spacing between elements of SX
!>
```

**Author**

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

**Further Details:**

```
!>
!>     jack dongarra, linpack, 3/11/78.
!>     modified 3/93 to return if incx .le. 0.
!>     modified 12/3/93, array(1) declarations changed to array(*)
!>
```

Definition at line **70** of file **isamax.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.