?lauum

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 11/07/2023

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?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

call slauum( uplo, n, a, lda, info )

call dlauum( uplo, n, a, lda, info )

call clauum( uplo, n, a, lda, info )

call zlauum( uplo, n, a, lda, info )

Include Files

mkl.fi

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

The data types are given for the Fortran interface.

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

INTEGER. 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 (lda, n).

On entry, the triangular factor U or L.

lda

INTEGER. 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).

info

INTEGER.

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.

Parent topic: LAPACK Auxiliary Routines

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Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

?lauum

Syntax

Include Files

Description

Input Parameters

Output Parameters