Developer Reference

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

p?pttrs

Solves a system of linear equations with a symmetric (Hermitian) positive-definite tridiagonal distributed matrix using the factorization computed by
p?pttrf
.

Syntax

call pspttrs
(
n
,
nrhs
,
d
,
e
,
ja
,
desca
,
b
,
ib
,
descb
,
af
,
laf
,
work
,
lwork
,
info
)
call pdpttrs
(
n
,
nrhs
,
d
,
e
,
ja
,
desca
,
b
,
ib
,
descb
,
af
,
laf
,
work
,
lwork
,
info
)
call pcpttrs
(
uplo
,
n
,
nrhs
,
d
,
e
,
ja
,
desca
,
b
,
ib
,
descb
,
af
,
laf
,
work
,
lwork
,
info
)
call pzpttrs
(
uplo
,
n
,
nrhs
,
d
,
e
,
ja
,
desca
,
b
,
ib
,
descb
,
af
,
laf
,
work
,
lwork
,
info
)
Include Files
Description
The
p?pttrs
routine
solves for
X
a system of distributed linear equations in the form:
sub(
A
)*
X
= sub(
B
) ,
where sub(
A
) =
A
(1:
n
,
ja
:
ja
+
n
-1) is an
n
-by-
n
real symmetric or complex Hermitian positive definite tridiagonal distributed matrix, and sub(
B
) denotes the distributed matrix
B
(
ib
:
ib
+
n
-1, 1:
nrhs
).
This
routine
uses the factorization
sub(
A
) =
P
*
L
*
D
*
L
H
*
P
T
, or sub(
A
) =
P
*
U
H
*
D
*
U
*
P
T
computed by
p?pttrf
.
Input Parameters
uplo
(global, used in complex flavors only)
CHARACTER*1
.
Must be
'U'
or
'L'
.
If
uplo
=
'U'
, upper triangle of sub(
A
) is stored;
If