---
name: "asum"
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/asum"
---

# asum(3)

asum: sum \| real( x\_i ) \| + \| imag( x\_i ) \|

## NAME

asum - asum: sum \| real( x\_i ) \| + \| imag( x\_i ) \|

## SYNOPSIS

### Functions

double precision function **dasum** (n, dx, incx)\
 **DASUM**  double precision function **dzasum** (n, zx, incx)\
 **DZASUM**  real function **sasum** (n, sx, incx)\
 **SASUM**  real function **scasum** (n, cx, incx)\
 **SCASUM**

## Detailed Description

## Function Documentation

### double precision function dasum (integer n, double precision, dimension(\*) dx, integer incx)

**DASUM**

**Purpose:**

```
!>
!>    DASUM takes the sum of the absolute values.
!>
```

**Parameters**

*N*

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

*DX*

```
!>          DX is DOUBLE PRECISION array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
!>
```

*INCX*

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

**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 **dasum.f**.

### double precision function dzasum (integer n, complex\*16, dimension(\*) zx, integer incx)

**DZASUM**

**Purpose:**

```
!>
!>    DZASUM takes the sum of the (|Re(.)| + |Im(.)|)'s of a complex vector and
!>    returns a double precision result.
!>
```

**Parameters**

*N*

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

*ZX*

```
!>          ZX is COMPLEX*16 array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
!>
```

*INCX*

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

**Author**

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

**Further Details:**

```
!>
!>     jack dongarra, 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 **71** of file **dzasum.f**.

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

**SASUM**

**Purpose:**

```
!>
!>    SASUM takes the sum of the absolute values.
!>    uses unrolled loops for increment equal to one.
!>
```

**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 **71** of file **sasum.f**.

### real function scasum (integer n, complex, dimension(\*) cx, integer incx)

**SCASUM**

**Purpose:**

```
!>
!>    SCASUM takes the sum of the (|Re(.)| + |Im(.)|)'s of a complex vector and
!>    returns a single precision result.
!>
```

**Parameters**

*N*

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

*CX*

```
!>          CX is COMPLEX 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 **71** of file **scasum.f**.

## Author

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