.. _D4.06.40:

**d4.06.40** An example of a distributed matrix for PETSc
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**Summary:**

To use the solvers from the PETSc library in parallel, you must provide an assembled matrix distributed across the available processors according to a distribution model imposed by PETSc (distribution by group of contiguous rows). The *Code_Aster* data distribution model is based on a distribution of meshes between processors. It leads to an assembled matrix that does not follow the PETSc distribution model. We explain here using a simple physical example the different numberings of the degrees of freedom: local and global numbering for Code_Aster then numbering PETSc.


.. toctree::
    :hidden:

    self

.. toctree::
    :maxdepth: 2
    :numbered:

    Introduction
    Probl_me_mod_le
    G_n_ralit_s_sur_le_syst_me_lin_aire
    Le_syst_me_lin_aire_pour_la_mod_lisation_A
    Le_syst_me_lin_aire_pour_la_mod_lisation_B
    Construction_de_la_matrice_PETSc_