Developer Reference for Intel® oneAPI Math Kernel Library for Fortran
?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.
Return Values
No return value, info is an Output Parameter.