?unmqr
?unmqr
Multiplies a complex matrix by the unitary matrix Q of the QR factorization formed by
?geqrf
. Syntax
lapack_int
LAPACKE_cunmqr
(
int
matrix_layout
,
char
side
,
char
trans
,
lapack_int
m
,
lapack_int
n
,
lapack_int
k
,
const
lapack_complex_float
*
a
,
lapack_int
lda
,
const
lapack_complex_float
*
tau
,
lapack_complex_float
*
c
,
lapack_int
ldc
);
lapack_int
LAPACKE_zunmqr
(
int
matrix_layout
,
char
side
,
char
trans
,
lapack_int
m
,
lapack_int
n
,
lapack_int
k
,
const
lapack_complex_double
*
a
,
lapack_int
lda
,
const
lapack_complex_double
*
tau
,
lapack_complex_double
*
c
,
lapack_int
ldc
);
Include Files
- mkl.h
Description
Depending on the parameters
side
and trans
, the routine can form one of the matrix products Q*C
, Q
H
*C
, C*Q
, or C*Q
H
(overwriting the result on C
).Input Parameters
- matrix_layout
- Specifies whether matrix storage layout is row major (LAPACK_ROW_MAJOR) or column major (LAPACK_COL_MAJOR).
- side
- Must be either'L'or'R'.If,side='L'QorQHis applied toCfrom the left.If,side='R'QorQHis applied toCfrom the right.
- trans
- Must be either'N'or'C'.If, the routine multipliestrans='N'CbyQ.If, the routine multipliestrans='C'CbyQ.H
- m
- The number of rows in the matrixC().m≥0
- n
- The number of columns inC().n≥0
- k
- The number of elementary reflectors whose product defines the matrixQ. Constraints:0if≤k≤m;side='L'0if≤k≤n.side='R'
- a,c,tau
- Arrays:asize max(1,andlda*k) for column major layout, max(1,lda*m) for row major layout whenside='L', and max(1,lda*n) for row major layout when side ='R'tauare the arrays returned bycgeqrf/zgeqrforcgeqpf/zgeqpf.The size oftaumust be at least max(1,k).c(size max(1,contains theldc*n) for column major layout and max(1,ldc*mfor row major layout)m-by-nmatrixC.
- lda
- The leading dimension ofa. Constraints:lda≥max(1,m)for column major layout andiflda≥max(1,k) for row major layout;side='L'lda≥max(1,n)for column major layout andiflda≥max(1,k) for row major layout.side='R'
- ldc
- The leading dimension ofc. Constraint:ldc≥max(1,m)for column major layout and max(1,.n) for row major layout
Output Parameters
- c
- Overwritten by the productQ*C,QH*C,C*Q, orC*Q(as specified byHsideandtrans).
Return Values
This function returns a value
info
.If , the execution is successful.
info
=0If , the
info
= -i
i
-th parameter had an illegal value.Application Notes
The real counterpart of this routine is ormqr.