?lansy

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 4/28/2026

Version

Public

?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

valslansy ( norm , uplo , n , a , lda , work )

valdlansy ( norm , uplo , n , a , lda , work )

valclansy ( norm , uplo , n , a , lda , work )

valzlansy ( norm , uplo , n , a , lda , work )

Include Files

mkl.fi

Description

slansy dlansy clansy zlansy

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

The data types are given for the Fortran interface.

norm

CHARACTER*1 . 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: CHARACTER*1 . 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

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

a

REAL for slansy DOUBLE PRECISION for dlansy COMPLEX for clansy DOUBLE COMPLEX for zlansy

Array, size ( 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

INTEGER . The leading dimension of the array a .

lda ≥ max( n ,1).

work: REAL for slansy and clansy . DOUBLE PRECISION for dlansy and zlansy . Workspace array, DIMENSION (max(1,lwork)) , where lwork≥n when norm = 'I' or ‘1’ or ‘O’ ; otherwise, work is not referenced.

Output Parameters

val: REAL for slansy / clansy DOUBLE PRECISION for dlansy / zlansy Value returned by the function.

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Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

?lansy

Syntax

Include Files

Description

Input Parameters

Output Parameters