Principle of the test
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The purpose of the test is to validate the programming of the PROD_MATR_CHAM command for real matrices (mrmult.f routine).

3 scenarios are verified for homogeneous *non* boundary conditions:


1. Boundary conditions eliminated (AFFE_CHAR_CINE)


2. Dualized boundary conditions (AFFE_CHAR_MECA + DDL_IMPO + LIAISON_DDL)


3. mixture between dualized and eliminated boundary conditions

For each case:


* We solve (commands FACTORISER + RESOUDRE) a linear system :math:`K\mathrm{\times }U\mathrm{=}F` with :math:`K` and :math:`F` known. We get :math:`U`.


* We then perform the product :math:`\mathit{FF}\mathrm{=}K\mathrm{\times }U` with the command PROD_MATR_CHAM and we check that :math:`\mathit{FF}` is equal to :math:`F`.