Contents

?dttrsb

Solves a system of linear equations with a diagonally dominant tridiagonal coefficient matrix using the LU factorization computed by
?dttrfb
.

Syntax

Include Files
• mkl.h
Description
The
?dttrsb
routine solves the following systems of linear equations with multiple right hand sides for
X
:
A
*
X
=
B
if
trans
=
'N'
,
A
T
*
X
=
B
if
trans
=
'T'
,
A
H
*
X
=
B
if
trans
=
'C'
(for complex matrices only).
Before calling this routine, call
?dttrfb
to compute the factorization of
A
.
Input Parameters
trans
Must be
'N'
or
'T'
or
'C'
.
Indicates the form of the equations solved for
X
:
If
trans
=
'N'
, then
A
*
X
=
B
.
If
trans
=
'T'
, then
A
T
*
X
=
B
.
If
trans
=
'C'
, then
A
H
*
X
=
B
.
n
The order of
A
;
n
0.
nrhs
The number of right-hand sides, that is, the number of columns in
B
;
nrhs
0.
dl
,
d
,
du
Arrays:
dl
(
n
-1)
,
d
(
n
)
,
du
(
n
-1)
.
The array
dl
contains the
(
n
- 1)
multipliers that define the matrices
L
1
,
L
2
from the factorization of
A
.
The array
d
contains the
n
diagonal elements of the upper triangular matrix
U
from the factorization of
A
.
The array
du
contains the (
n
- 1) elements of the superdiagonal of
U
.
b
Array of size max(1,
ldb
*
nrhs
). Contains the matrix
B
whose columns are the right-hand sides for the systems of equations.
ldb
The leading dimension of
b
;
ldb
max(1,
n
)
.
Output Parameters
b
Overwritten by the solution matrix
X
.
info
If
info
= 0
, the execution is successful.
If
info
=
-i
, the
i
-th parameter had an illegal value.

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804