Code_Aster
®
Version
8.2
Titrate:
Operator
RESO_LDLT
Date:
31/01/06
Author (S):
J. PELLET
Key
:
U4.55.02-I1
Page
:
1/4
Instruction manual
U4.5- booklet: Methods of resolution
HT-62/06/004/A
Organization (S):
EDF-R & D/AMA
Instruction manual
U4.5- booklet: Methods of resolution
Document: U4.55.02
Operator
RESO_LDLT
1 Goal
To solve a system of linear equations by a “direct” method.
The operator allows real or complex resolutions. The matrix must have been beforehand
factorized by control FACT_LDLT [U4.55.01].
In spite of its name, this control corresponds to the three established methods of “direct” resolution
in Aster: the resolution
LDLT
, the method multifrontale and method MUMPS. The effective choice of
method is done through the control
NUME_DDL
[U4.61.11].
The resolution by combined gradient is done by the control
RESO_GRAD
[U4.55.04].
Product a structure of data of the cham_no_ type *.
Code_Aster
®
Version
8.2
Titrate:
Operator
RESO_LDLT
Date:
31/01/06
Author (S):
J. PELLET
Key
:
U4.55.02-I1
Page
:
2/4
Instruction manual
U4.5- booklet: Methods of resolution
HT-62/06/004/A
2 Syntax
U
[cham_no_ *]
=
RESO_LDLT
(
reuse = U,
MATR_FACT
=
With,
/
[matr_asse_DEPL_R]
/
[matr_asse_DEPL_C]
/
[matr_asse_TEMP_R]
/
[matr_asse_TEMP_C]
/
[matr_asse_PRES_R]
/
[matr_asse_PRES_C]
CHAM_NO
=
B,
/
[cham_no_DEPL_R]
/
[cham_no_DEPL_C]
/
[cham_no_TEMP_R]
/
[cham_no_TEMP_C]
/
[cham_no_PRES_R]
/
[cham_no_PRES_C]
CHAM_CINE
= vcine,/[cham_no_DEPL_R]
/
[cham_no_TEMP_R]
/
[cham_no_PRES_C]
# if solvor MUMPS:
RESI_RELA
=/1.e-6, [DEFECT]
/
eps
, [R]
TITRATE
= titr,
[l_K80]
INFORMATION
=
/1, [DEFECT]
/
2
,
)
if CHAM_NO:
[cham_no_DEPL_R] then [*]
- >
DEPL_R
[cham_no_DEPL_C]
DEPL_C
[cham_no_TEMP_R]
TEMP_R
[cham_no_TEMP_C]
TEMP_C
[cham_no_PRES_R]
PRES_R
[cham_no_PRES_C]
PRES_C
Code_Aster
®
Version
8.2
Titrate:
Operator
RESO_LDLT
Date:
31/01/06
Author (S):
J. PELLET
Key
:
U4.55.02-I1
Page
:
3/4
Instruction manual
U4.5- booklet: Methods of resolution
HT-62/06/004/A
3 General information
This control makes it possible to solve the linear systems
AX
B
=
where
With
is a matrix
“factorized beforehand” by the control
FACT_LDLT
[U4.51.01].
The resolution is possible for boundary conditions of DIRICHLET (boundary conditions
kinematics) dualized or eliminated [U2.01.02]. In this last case, if the loading
X
X
=
0
on the “edge”
0
was translated by a kinematic load (operator
AFFE_CHAR_CINE
[U4.44.03]
taking into account in the assembled matrix (operator
ASSE_MATRICE
[U4.61.22], the “value” of it
loading
()
X
0
, calculated by the operator
CALC_CHAR_CINE
[U4.61.03] must be provided by the word
key
CHAM_CINE
.
4 Operands
4.1 Operand
MATR_FACT
MATR_FACT = A,
Name of the factorized matrix, concept produced by the operator
FACT_LDLT
. This matrix can be
real or complex, symmetrical or not.
4.2 Operand
CHAM_NO
CHAM_NO = B
,
Name of the vector second member (in general obtained by control ASSE_VECTEUR).
4.3 Operand
CHAM_CINE
CHAM_CINE = vcine,
Name of the vector representing the “value” of the boundary conditions of the translated type “DIRICHLET”
in the form of kinematic loading (i.e. by use of one of the controls
AFFE_CHAR_CINE
or
AFFE_CHAR_CINE_F
).
It
cham_no
comes from the execution of the operator
CALC_CHAR_CINE
on the list of
char_cine
(loadings kinematics) associated the assembled matrix
With
[U2.01.02].
4.4 Operand
RESI_RELA
RESI_RELA = 1.e-6 (defect)/eps
This key word is described in [U4.50.01]
4.5 Operand
TITRATE
TITRATE =
titr,
Titrate that one wants to give to the produced result [U4.03.01].
4.6 Operand
INFORMATION
INFORMATION =
1
: no impression.
Code_Aster
®
Version
8.2
Titrate:
Operator
RESO_LDLT
Date:
31/01/06
Author (S):
J. PELLET
Key
:
U4.55.02-I1
Page
:
4/4
Instruction manual
U4.5- booklet: Methods of resolution
HT-62/06/004/A
5 Examples
·
Constitution of the assembled matrices:
The elementary terms before were calculated
Kel
,
Fel
.
naked = NUME_DDL (MATR_RIGI = Kel)
Kass =
ASSE_MATRICE
(MATR_ELEM = Kel,
NUME_DDL = naked,)
Fass =
ASSE_VECTEUR
(MATR_ELEM = Fel,
NUME_DDL = naked,)
·
Factorization in place:
Kass
= FACT_LDLT
(reuse = Kass,
MATR_ASSE = Kass,
)
·
Out-place resolution:
Uass
= RESO_LDLT
(MATR_FACT = Kass, CHAM_NO = Fass,)
·
Resolution in place:
Fass =
RESO_LDLT
(reuse=Fass,
MATR_FACT=Kass, CHAM_NO=Fass,)
·
for the use of the loads kinematics (with elimination of the imposed degrees of freedom), to see
the example given in the control
AFFE_CHAR_CINE
[U4.44.03].