?lauum

Developer Reference for Intel® oneAPI Math Kernel Library for C

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ID 766684

Date 4/28/2026

Version

Public

?lauum

Computes the product U*U^{T} ( U*U^{H} ) or L^{T}*L ( L^{H}*L ), where U and L are upper or lower triangular matrices (blocked algorithm).

Syntax

lapack_intLAPACKE_slauum ( intmatrix_layout , charuplo , lapack_intn , float*a , lapack_intlda );

lapack_intLAPACKE_dlauum ( intmatrix_layout , charuplo , lapack_intn , double*a , lapack_intlda );

lapack_intLAPACKE_clauum ( intmatrix_layout , charuplo , lapack_intn , lapack_complex_float*a , lapack_intlda );

lapack_intLAPACKE_zlauum ( intmatrix_layout , charuplo , lapack_intn , lapack_complex_double*a , lapack_intlda );

Include Files

mkl.h

Description

The routine ?lauum computes the product U*U^{T} or L^{T}*L for real flavors, and U*U^{H} or L^{H}*L for complex flavors. Here the triangular factor U or L is stored in the upper or lower triangular part of the array a .

If uplo = 'U' or ‘u’ , then the upper triangle of the result is stored, overwriting the factor U in A .

If uplo = 'L' or ‘l’ , then the lower triangle of the result is stored, overwriting the factor L in A .

This is the blocked form of the algorithm, calling BLAS Level 3 Routines .

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.

uplo: CHARACTER*1 . Specifies whether the triangular factor stored in the array a is upper or lower triangular: = ‘U’ : Upper triangular = ‘L’ : Lower triangular

n

The order of the triangular factor U or L . n≥ 0 .

a

REAL for slauum DOUBLE PRECISION for dlauum COMPLEX for clauum DOUBLE COMPLEX for zlauum .

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

On entry, the triangular factor U or L .

lda

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

Output Parameters

a: On exit, if uplo = 'U' , then the upper triangle of a is overwritten with the upper triangle of the product U*U^{T} ( U*U^{H} ); if uplo = 'L' , then the lower triangle of a is overwritten with the lower triangle of the product L^{T}*L ( L^{H}*L ).

Return Values

This function returns a value info .

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

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Developer Reference for Intel® oneAPI Math Kernel Library for C

?lauum

Syntax

Include Files

Description

Input Parameters

Output Parameters

Return Values