## Developer Reference

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

# ?sysv_rook

Computes the solution to the system of linear equations with a real or complex symmetric coefficient matrix A and multiple right-hand sides.

## Syntax

Include Files
• mkl.fi
,
lapack.f90
Description
The routine solves for
X
the real or complex system of linear equations
A*X
=
B
, where
A
is an
n
-by-
n
symmetric matrix, the columns of matrix
B
are individual right-hand sides, and the columns of
X
are the corresponding solutions.
The diagonal pivoting method is used to factor
A
as
A
=
U*D*U
T
or
A
=
L*D*L
T
, where
U
(or
L
) is a product of permutation and unit upper (lower) triangular matrices, and
D
is symmetric and block diagonal with 1-by-1 and 2-by-2 diagonal blocks.
The
?sysv_rook
routine is called to compute the factorization of a complex symmetric matrix
A
using the bounded Bunch-Kaufman ("rook") diagonal pivoting method.
The factored form of
A
is then used to solve the system of equations
A*X
=
B
.
Input Parameters
uplo
CHARACTER*1
.
Must be
'U'
or
'L'
.
Indicates whether the upper or lower triangular part of
A
is stored:
If
uplo
=
'U'
, the upper triangle of
A
is stored.
If
uplo
=
'L'
, the lower triangle of
A
is stored.
n
INTEGER
.
The order of matrix
A
;
n