Developer Reference for Intel® oneAPI Math Kernel Library for Fortran
?lauu2
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 (unblocked algorithm).
Syntax
call slauu2 ( uplo , n , a , lda , info )
call dlauu2 ( uplo , n , a , lda , info )
call clauu2 ( uplo , n , a , lda , info )
call zlauu2 ( uplo , n , a , lda , info )
Include Files
mkl.fi
Description
The routine ?lauu2 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 unblocked form of the algorithm, calling BLAS Level 2 Routines .
Input Parameters
- 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 slauu2 DOUBLE PRECISION for dlauu2 COMPLEX for clauu2 DOUBLE COMPLEX for zlauu2 . Array, DIMENSION ( 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 .
= 0: successful exit
< 0: if info = -k , the k -th argument had an illegal value