Examples
========


Solving by the direct method MULT_FRONT
--------------------------------------------


* Composition of the assembled matrix and of the second member:

We have previously calculated the elementary terms KEL, FEL.


.. code-block:: text
 NAKED = NUME_DDL (MATR_RIGI = KEL)
K = ASSE_MATRICE (MATR_ELEM = KEL, NUME_DDL =NAKED,)
F = ASSE_VECTEUR (MATR_ELEM = FEL, NUME_DDL =NAKED,)


* Factorization:


.. code-block:: text
 K = FACTORISER (reuse=K, MATR_ASSE =K, =K, METHODE =' MULT_FRONT ',)


* Resolution:


.. code-block:: text
 U = RESOUDRE (MATR =K, CHAM_NO =F,)


* for the use of kinematic loads (with the elimination of imposed degrees of freedom), see the example given in command AFFE_CHAR_CINE [:external:ref:`U4.44.03 <U4.44.03>`].


Solving by the MUMPS method
-------------------------------


.. code-block:: text

    NAKED = NUME_DDL (MATR_RIGI = KEL)


    K = ASSE_MATRICE (MATR_ELEM = KEL, NUME_DDL = NU)

    F = ASSE_VECTEUR (VECT_ELEM = FEL, NUME_DDL = NU)

    K = FACTORISER (reuse= K, MATR_ASSE = K, METHODE = 'MUMPS')

    dep = RESOUDRE (CHAM_NO = F, MATR = K)


Resolution by the preconditioned conjugate gradient method
--------------------------------------------------------------


.. code-block:: text

    NAKED = NUME_DDL (MATR_RIGI = KEL)


    K = ASSE_MATRICE (MATR_ELEM = KEL, NUME_DDL = NU)

    F = ASSE_VECTEUR (VECT_ELEM = FEL, NUME_DDL = NU)

    KPREC = FACTORISER (MATR_ASSE = K, METHODE = 'GCPC',
PRE_COND =' LDLT_INC ')

    dep = RESOUDRE (CHAM_NO = F, MATR = K, MATR_PREC = KPREC,
NMAX_ITER = 1000, RESI_RELA = 1e-07
)


Solving by the PETSC method
-------------------------------


.. code-block:: text

    NAKED = NUME_DDL (MATR_RIGI = KEL)


    K = ASSE_MATRICE (MATR_ELEM = KEL, NUME_DDL = NU)

    F = ASSE_VECTEUR (VECT_ELEM = FEL, NUME_DDL = NU)

    K = FACTORISER (refuse=K, MATR_ASSE = K, METHODE = 'PETSC')

    dep = RESOUDRE (CHAM_NO = F, MATR = K, MATR_PREC = K,
ALGORITHME =' GMRES ',
NMAX_ITER = 1000, RESI_RELA = 1e-07)