Generalities
===========

The function of this object of type SOLVEUR is to store and convey between the various routines of the code (within a command or between commands), the information related to the settings of the linear solvers. In particular, it defines the method for solving single-domain linear systems (LDLT, MULT_FRONT, PETSC, MUMPS or GCPC). This object is created on a volatile basis (the most frequent case) or on a global basis (exploded commands).

Most often, it is created and filled *via* CRESOL/CRSV ** (first two letters of the solver: MU for MUMPS direct solver and CRSMSP for MUMPS preconditioner, PE for PETSC, LD for LDLT, LD for, GC for GCPC and MF for MULT_FRONT).

To respond to a few specific cases, other dedicated routines create and fill out a SD_SOLVEUR: CRSOLV [1] _
, OP0014 [2] _
and CRSINT [3] _
. We try to limit the number of them and to favor the use of the main routine: CRESOL.

Regardless of the routine that creates the objects in data structure SOLVEUR, the sizing is done exclusively in a hat routine: SDSOLV.

*When modifying this data structure, care must therefore be taken to:*


* *harmonize, if necessary, the sources mentioned above,*


* *update the catalog* *sd_solveur.py,*


* *update the documentation (this doc. D and if necessary the doc. U4.50.01),*


* *enrich or modify, if necessary, some test cases.*




.. [1] For CALC_CORR_SSD, MODE_STATIQUE, NUME_DDL_GENE,, NUME_DDL, MACR_ELEM_STAT.
.. [2] For FACTORISER.
.. [3] For an underhand call from MUMPS in MODE_STATIQUE and CALC_CORR_SSD.