Developer Reference

Contents

?dttrf

Computes an LU factorization of a general tridiagonal matrix with no pivoting (local blocked algorithm).

Syntax

void
sdttrf
(
MKL_INT
*n
,
float
*dl
,
float
*d
,
float
*du
,
MKL_INT
*info
);
void
ddttrf
(
MKL_INT
*n
,
double
*dl
,
double
*d
,
double
*du
,
MKL_INT
*info
);
void
cdttrf
(
MKL_INT
*n
,
MKL_Complex8
*dl
,
MKL_Complex8
*d
,
MKL_Complex8
*du
,
MKL_INT
*info
);
void
zdttrf
(
MKL_INT
*n
,
MKL_Complex16
*dl
,
MKL_Complex16
*d
,
MKL_Complex16
*du
,
MKL_INT
*info
);
Include Files
  • mkl_scalapack.h
Description
The
?dttrf
function
computes an
LU
factorization of a real or complex tridiagonal matrix
A
using elimination without partial pivoting.
The factorization has the form
A
=
L*U
, where
L
is a product of unit lower bidiagonal matrices and
U
is upper triangular with nonzeros only in the main diagonal and first superdiagonal.
Input Parameters
n
The order of the matrix
A
(
n
0)
.
dl
,
d
,
du
Arrays containing elements of
A
.
The array
dl
of size
(
n
-1)
contains the sub-diagonal elements of
A
.
The array
d
of size
n
contains the diagonal elements of
A
.
The array
du
of size
(
n
-1)
contains the super-diagonal elements of
A
.
Output Parameters
dl
Overwritten by the
(
n
-1)
multipliers that define the matrix
L
from the
LU
factorization of
A
.
d
Overwritten by the
n
diagonal elements of the upper triangular matrix
U
from the
LU
factorization of
A
.
du
Overwritten by the
(
n
-1)
elements of the first super-diagonal of
U
.
info
= 0: successful exit
< 0: if
info
= -
i
, the
i
-th argument had an illegal value,
> 0: if
info
=
i
,
the matrix element
U
(
i
,
i
)
is exactly 0. The factorization has been completed, but the factor
U
is exactly singular. Division by 0 will occur if you use the factor
U
for solving a system of linear equations.

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