?lansy

Developer Reference for Intel® oneAPI Math Kernel Library for C

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ID 766684

Date 6/24/2024

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?lansy

Returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a real/complex symmetric matrix.

Syntax

float LAPACKE_slansy (int matrix_layout, char norm, char uplo, lapack_int n, const float * a, lapack_int lda);

double LAPACKE_dlansy (int matrix_layout, char norm, char uplo, lapack_int n, const double * a, lapack_int lda);

float LAPACKE_clansy (int matrix_layout, char norm, char uplo, lapack_int n, const lapack_complex_float * a, lapack_int lda);

double LAPACKE_zlansy (int matrix_layout, char norm, char uplo, lapack_int n, const lapack_complex_double * a, lapack_int lda);

Include Files

mkl.h

Description

The function ?lansy returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a real/complex symmetric matrix A.

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.

norm

Specifies the value to be returned by the routine:

= 'M' or 'm': val = max(abs(A_ij)), largest absolute value of the matrix A.

= '1' or 'O' or 'o': val = norm1(A), 1-norm of the matrix A (maximum column sum),

= 'I' or 'i': val = normI(A), infinity norm of the matrix A (maximum row sum),

= 'F', 'f', 'E' or 'e': val = normF(A), Frobenius norm of the matrix A (square root of sum of squares).

uplo

Specifies whether the upper or lower triangular part of the symmetric matrix A is to be referenced.

= 'U': Upper triangular part of A is referenced.

= 'L': Lower triangular part of A is referenced

n

The order of the matrix A. n≥ 0. When n = 0, ?lansy is set to zero.

a

Array, size at least max(1,lda*n). The symmetric matrix A.

If uplo = 'U', the leading n-by-n upper triangular part of a contains the upper triangular part of the matrix A, and the strictly lower triangular part of a is not referenced.

If uplo = 'L', the leading n-by-n lower triangular part of a contains the lower triangular part of the matrix A, and the strictly upper triangular part of a is not referenced.

lda

The leading dimension of the array a.

lda≥ max(n,1).

Parent topic: LAPACK Auxiliary Routines

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Developer Reference for Intel® oneAPI Math Kernel Library for C

?lansy

Syntax

Include Files

Description

Input Parameters