Developer Reference for Intel® oneAPI Math Kernel Library for Fortran
b?laapp
Multiplies a matrix with an orthogonal matrix.
Syntax
call bslaapp ( iside , m , n , nb , a , lda , nitraf , itraf , dtraf , work )
call bdlaapp ( iside , m , n , nb , a , lda , nitraf , itraf , dtraf , work )
Include Files
mkl_scalapack.h
Description
b?laapp computes
B = QTA or B = AQ
where A is an m -by- n matrix and Q is an orthogonal matrix represented by the parameters in the arrays itraf and dtraf as described in b?trexc (Reorders the Schur factorization of a general matrix.) .
This is an auxiliary routine function called by p?trord (Reorders the Schur factorization of a general matrix.) .
Input Parameters
- iside
-
INTEGER Specifies whether Q multiplies A from the left or right as follows: = 0: compute B = QTA ; = 1: compute B = AQ .
- m
-
INTEGER The number of rows of A .
- n
-
INTEGER The number of columns of A .
- nb
-
INTEGER If iside = 0, the Q is applied block column-wise to the rows of A and nb specifies the maximal width of the block columns. If iside = 1, this variable is not referenced.
- a
-
REAL for bslaapp DOUBLE PRECISION for bdlaapp
Array of size ( lda , n ) .
On entry, the matrix A .
- lda
-
INTEGER The leading dimension of the array a . lda ≥ max(1, n ).
- nitraf
-
INTEGER Length of the array itraf . nitraf ≥ 0.
itraf
INTEGER array, length nitraf
List of parameters for representing the transformation matrix Q , see b?trexc (Reorders the Schur factorization of a general matrix.) .
work
(workspace) REAL array of size n .
OUTPUT Parameters
- a
-
a is overwritten by B .
- dtraf
-
REAL for bslaapp DOUBLE PRECISION for bdlaapp Array, length k . If iside =0, k = 3*( n / nb ). If iside =1, k = 3* nitraf . List of parameters for representing the transformation matrix Q , see b?trexc (Reorders the Schur factorization of a general matrix.)