Developer Reference

  • 2020.2
  • 07/15/2020
  • Public Content
Contents

p?dttrsv

Computes an LU factorization of a general band matrix, using partial pivoting with row interchanges. The
routine
is called by
p?dttrs
.

Syntax

call psdttrsv
(
uplo
,
trans
,
n
,
nrhs
,
dl
,
d
,
du
,
ja
,
desca
,
b
,
ib
,
descb
,
af
,
laf
,
work
,
lwork
,
info
)
call pddttrsv
(
uplo
,
trans
,
n
,
nrhs
,
dl
,
d
,
du
,
ja
,
desca
,
b
,
ib
,
descb
,
af
,
laf
,
work
,
lwork
,
info
)
call pcdttrsv
(
uplo
,
trans
,
n
,
nrhs
,
dl
,
d
,
du
,
ja
,
desca
,
b
,
ib
,
descb
,
af
,
laf
,
work
,
lwork
,
info
)
call pzdttrsv
(
uplo
,
trans
,
n
,
nrhs
,
dl
,
d
,
du
,
ja
,
desca
,
b
,
ib
,
descb
,
af
,
laf
,
work
,
lwork
,
info
)
Description
The
p?dttrsv
routine
solves a tridiagonal triangular system of linear equations
A
(1 :
n
,
ja
:
ja
+
n
-1)
*
X
=
B
(
ib
:
ib
+
n
-1, 1 :
nrhs
)
or
A
(1 :
n
,
ja
:
ja
+
n
-1)
T
*
X
=
B
(
ib
:
ib
+
n
-1, 1 :
nrhs
)
for real flavors;
A
(1 :
n
,
ja
:
ja
+
n
-1)
H
*
X
=
B
(
ib
:
ib
+
n
-1, 1 :
nrhs
)
for complex flavors,
where
A
(1 :
n
,
ja
:
ja
+
n
-1)
is a tridiagonal matrix factor produced by the Gaussian elimination code of
p?dttrf
and is stored in
A
(1 :
n
,
ja
:
ja
+
n
-1)
and
af
.
The matrix stored in
A
(1 :
n
,
ja
:
ja
+
n
-1)
is either upper or lower triangular according to
uplo
, and the choice of solving
A
(1 :
n
,
ja
:
ja
+
n
-1)
or
A
(1 :
n
,
ja
:
ja
+
n
-1)
T
is dictated by the user by the parameter
trans
.
The routine
p?dttrf
must be called first.
Input Parameters
uplo
(global)
CH