---
name: "dsyswapr.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/dsyswapr.f"
---

# dsyswapr.f(3)

## NAME

SRC/dsyswapr.f

## SYNOPSIS

### Functions/Subroutines

subroutine **dsyswapr** (uplo, n, a, lda, i1, i2)\
 **DSYSWAPR** applies an elementary permutation on the rows and columns of a symmetric matrix.

## Function/Subroutine Documentation

### subroutine dsyswapr (character uplo, integer n, double precision, dimension( lda, \* ) a, integer lda, integer i1, integer i2)

**DSYSWAPR** applies an elementary permutation on the rows and columns of a symmetric matrix.

**Purpose:**

```
!>
!> DSYSWAPR applies an elementary permutation on the rows and the columns of
!> a symmetric matrix.
!>
```

**Parameters**

*UPLO*

```
!>          UPLO is CHARACTER*1
!>          Specifies whether the details of the factorization are stored
!>          as an upper or lower triangular matrix.
!>          = 'U':  Upper triangular, form is A = U*D*U**T;
!>          = 'L':  Lower triangular, form is A = L*D*L**T.
!>
```

*N*

```
!>          N is INTEGER
!>          The order of the matrix A.  N >= 0.
!>
```

*A*

```
!>          A is DOUBLE PRECISION array, dimension (LDA,*)
!>          On entry, the N-by-N matrix A. On exit, the permuted matrix
!>          where the rows I1 and I2 and columns I1 and I2 are interchanged.
!>          If UPLO = 'U', the interchanges are applied to the upper
!>          triangular part and the strictly lower triangular part of A is
!>          not referenced; if UPLO = 'L', the interchanges are applied to
!>          the lower triangular part and the part of A above the diagonal
!>          is not referenced.
!>
```

*LDA*

```
!>          LDA is INTEGER
!>          The leading dimension of the array A.  LDA >= max(1,N).
!>
```

*I1*

```
!>          I1 is INTEGER
!>          Index of the first row to swap
!>
```

*I2*

```
!>          I2 is INTEGER
!>          Index of the second row to swap
!>
```

**Author**

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line **99** of file **dsyswapr.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.