?syswapr

Developer Reference for Intel® oneAPI Math Kernel Library for C

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ID 766684

Date 10/15/2026

Version

Public

?syswapr

Applies an elementary permutation on the rows and columns of a symmetric matrix.

Syntax

lapack_int LAPACKE_ssyswapr(int matrix_layout, char uplo, lapack_int n, float *a,
                            lapack_int i1, lapack_int i2);

lapack_int LAPACKE_dsyswapr(int matrix_layout, char uplo, lapack_int n, double *a,
                            lapack_int i1, lapack_int i2);

lapack_int LAPACKE_csyswapr(int matrix_layout, char uplo, lapack_int n,
                            lapack_complex_float *a, lapack_int i1, lapack_int i2);

lapack_int LAPACKE_zsyswapr(int matrix_layout, char uplo, lapack_int n,
                            lapack_complex_double *a, lapack_int i1, lapack_int i2);

Include Files

mkl.h

Description

The routine applies an elementary permutation on the rows and columns of a symmetric matrix.

Input Parameters

A <datatype> placeholder, if present, is used for the C interface data types in the C interface section above. See C Interface Conventions for the C interface principal conventions and type definitions.

matrix_layout

Specifies whether matrix storage layout is row major ( LAPACK_ROW_MAJOR ) or column major ( LAPACK_COL_MAJOR ).

uplo

Must be ‘U’ or ‘L’ .

Indicates how the input matrix A has been factored:

If uplo = 'U' , the array a stores the upper triangular factor U of the factorization A = U*D*U^{T} .

If uplo = 'L' , the array a stores the lower triangular factor L of the factorization A = L*D*L^{T} .

n: Specifies the order of the matrix A . The value of n must be at least zero.

nrhs

The number of right-hand sides; nrhs ≥ 0.

a

Array of size at least max (1,lda*n) .

The array a contains the block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by ?sytrf .

lda

INTEGER . The leading dimension of the array a . lda ≥ max (1, n ).

i1

Index of the first row to swap.

i2

Index of the second row to swap.

Output Parameters

a

If info = 0 , the symmetric inverse of the original matrix.

If info = 'U' , the upper triangular part of the inverse is formed and the part of A below the diagonal is not referenced.

If info = 'L' , the lower triangular part of the inverse is formed and the part of A above the diagonal is not referenced.

Return Values

This function returns a value info .

If info = 0 , the execution is successful.
If info = -i , the i -th parameter had an illegal value.
If info = -1011 , memory allocation error occurred.

LAPACK 95 Interface Notes

There exist FORTRAN 77 and FORTRAN 95 interfaces for this routine. See the Intel® oneMKL Fortran Developer Reference for details.

NOTE:

?sytrf

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Developer Reference for Intel® oneAPI Math Kernel Library for C

?syswapr

Syntax

Include Files

Description

Input Parameters

Output Parameters

Return Values

LAPACK 95 Interface Notes