F06ZFF (ZTRMM) (PDF version)
F06 Chapter Contents
F06 Chapter Introduction
NAG Library Manual
NAG Library Routine Document
F06ZFF (ZTRMM)
Note:
before using this routine, please read the Users' Note for your implementation to check the interpretation of
bold italicised
terms and other implementation-dependent details.
+
−
Contents
1
Purpose
2
Specification
3
Description
4
References
5
Parameters
6
Error Indicators and Warnings
7
Accuracy
8
Further Comments
9
Example
1 Purpose
F06ZFF (ZTRMM) performs one of the matrix-matrix operations
B
←
α
A
B
,
B
←
α
A
T
B
,
B
←
α
A
H
B
,
B
←
α
B
A
,
B
←
α
B
A
T
or
B
←
α
B
A
H
,
where
B
is an
m
by
n
complex matrix,
A
is a complex triangular matrix, and
α
is a complex scalar.
2 Specification
SUBROUTINE F06ZFF (
SIDE
,
UPLO
,
TRANSA
,
DIAG
,
M
,
N
,
ALPHA
,
A
,
LDA
,
B
,
LDB
)
INTEGER
M, N, LDA, LDB
COMPLEX (KIND=nag_wp)
ALPHA, A(LDA,*), B(LDB,*)
CHARACTER(1)
SIDE, UPLO, TRANSA, DIAG
The routine may be called by its BLAS name
ztrmm
.
3 Description
None.
4 References
None.
5 Parameters
1: SIDE – CHARACTER(1)
Input
On entry
: specifies whether
B
is operated on from the left or the right.
SIDE
=
'L'
B
is pre-multiplied from the left.
SIDE
=
'R'
B
is post-multiplied from the right.
Constraint
:
SIDE
=
'L'
or
'R'
.
2: UPLO – CHARACTER(1)
Input
On entry
: specifies whether
A
is upper or lower triangular.
UPLO
=
'U'
A
is upper triangular.
UPLO
=
'L'
A
is lower triangular.
Constraint
:
UPLO
=
'U'
or
'L'
.
3: TRANSA – CHARACTER(1)
Input
On entry
: specifies whether the operation involves
A
,
A
T
or
A
H
.
TRANSA
=
'N'
The operation involves
A
.
TRANSA
=
'T'
The operation involves
A
T
.
TRANSA
=
'C'
The operation involves
A
H
.
Constraint
:
TRANSA
=
'N'
,
'T'
or
'C'
.
4: DIAG – CHARACTER(1)
Input
On entry
: specifies whether
A
has nonunit or unit diagonal elements.
DIAG
=
'N'
The diagonal elements are stored explicitly.
DIAG
=
'U'
The diagonal elements are assumed to be
1
, and are not referenced.
Constraint
:
DIAG
=
'N'
or
'U'
.
5: M – INTEGER
Input
On entry
:
m
, the number of rows of the matrix
B
; the order of
A
if
SIDE
=
'L'
.
Constraint
:
M
≥
0
.
6: N – INTEGER
Input
On entry
:
n
, the number of columns of the matrix
B
; the order of
A
if
SIDE
=
'R'
.
Constraint
:
N
≥
0
.
7: ALPHA – COMPLEX (KIND=nag_wp)
Input
On entry
: the scalar
α
.
8: A(
LDA
,
*
) – COMPLEX (KIND=nag_wp) array
Input
Note:
the second dimension of the array
A
must be at least
max
1
,
M
if
SIDE
=
'L'
and at least
max
1
,
N
if
SIDE
=
'R'
.
On entry
: the triangular matrix
A
;
A
is
m
by
m
if
SIDE
=
'L'
, or
n
by
n
if
SIDE
=
'R'
.
If
UPLO
=
'U'
,
A
is upper triangular and the elements of the array below the diagonal are not referenced.
If
UPLO
=
'L'
,
A
is lower triangular and the elements of the array above the diagonal are not referenced.
If
DIAG
=
'U'
, the diagonal elements of
A
are assumed to be
1
, and are not referenced.
9: LDA – INTEGER
Input
On entry
: the first dimension of the array
A
as declared in the (sub)program from which F06ZFF (ZTRMM) is called.
Constraints
:
if
SIDE
=
'L'
,
LDA
≥
max
1
,
M
;
if
SIDE
=
'R'
,
LDA
≥
max
1
,
N
.
10: B(
LDB
,
*
) – COMPLEX (KIND=nag_wp) array
Input/Output
Note:
the second dimension of the array
B
must be at least
max
1
,
N
.
On entry
: the
m
by
n
matrix
B
.
If
ALPHA
=
0
,
B
need not be set.
On exit
: the updated matrix
B
.
11: LDB – INTEGER
Input
On entry
: the first dimension of the array
B
as declared in the (sub)program from which F06ZFF (ZTRMM) is called.
Constraint
:
LDB
≥
max
1
,
M
.
6 Error Indicators and Warnings
None.
7 Accuracy
Not applicable.
8 Further Comments
None.
9 Example
None.
F06ZFF (ZTRMM) (PDF version)
F06 Chapter Contents
F06 Chapter Introduction
NAG Library Manual
© The Numerical Algorithms Group Ltd, Oxford, UK. 2012