?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(Aij)), 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).

For more complete information about compiler optimizations, see our Optimization Notice.
Select sticky button color: 
Orange (only for download buttons)