CM2 FEM® Engines /release 4.3.0

• Lib names suffix is _43 for this series.
• New Visual Studio 2017 builds (Win32, Win64, MD, MT).
• New GCC 5 and GCC 6 builds (Linux86, Linux64).
• Visual Studio < 2010 and GCC < 4.8 are deprecated and will be no longer supported in future versions.
  In the long term, C++98 will be deprecated. C++11-compliant compilers (for instance Visual Studio >= 2015) will be required to compile the source code of CM2 but also to compile against its API.
• Windows XP is deprecated and will be no longer supported in future versions.
• macOS < 10.9 is deprecated and will be no longer supported in future versions (minimum deployment target will raise to 10.9 Mavericks).

law_shell_orthotropic

• Can now be initialized also with a mid-surface offset (init with 16 parameters, to be consistent with fem::law_shell_StVenant).

contact_contact, contact_cylinder, contact_sphere

• New optional penalty parameter En (default = DBL_MAX) to reduce the penalty parameter (the smallest value between En and the default context penalty is used).

contact_cylinder, contact_sphere

• New optional stabilize_flag (default = true) to remove the geometric stiffness when negative (happens only with radius > 0).

solver_response_spectrum::data_type

• New optional context parameter (used to get the max number of threads among others).
  This enables (partial) parallelization of the solver.

solver_Newmark (formerly solver_Newmark_linear)

• New settings_type::K_update_period to allow updates of the stiffness matrix (useful only when the stiffness is non-linear with respect to the current solution or when the model is evolving with time).
  As the computation and the factorization of the global stiffness matrix K usually outweighs all other computation times, it can be judicious not to update at every time step but only when the current solution has evolved enough to have a significant impact on the stiffness matrix.
  The default is K_update_period = 0 (compute and factorize K only at time = t0 and keep this matrix for all the time steps, as in prior versions of CM2 FEM).

solver_static_Newton

• New output vector data_type::elastic_energies for elastic energies after each step.

FEM_matrix, FEM_Zmatrix

• New member set_vector.

Miscellaneous

• RTTI enabled (except Math1 vector and matrix classes).
• Mechanical model classes: default constructors added.

All solvers

• Better usage of multi-core CPUs when solving multiple right-hand sides.
  This gives very significant speed-ups when the number of DOFs is greater than 100k on the modal solvers (fem::solver_modal, fem::solver_modal_LDRV, fem::solver_buckling_Euler) and on fem::solver_static_linear with multiple RHS.
• Parallelization of forward-reduction and backward-substitution (i.e. resolution after factorization) for one RHS.
  This gives also some noticeable speed-ups in modal solvers (and to a lower extent to all other solvers).
• Some noticeable speed-ups in the assembly step in all solvers.
• The DOFs numbering scheme is now reproducible (i.e. gives the same sequences across platforms/compilers).

Modal solvers (solver_modal, solver_modal_LDRV, solver_buckling_Euler)

• Better parallelization.

solver_response_spectrum, solver_condensation_static

• Partial parallelization.

Miscellaneous

• Port to Visual Studio 2017.
• Doc clarifications.

All solvers

• Degenerated elements in a mesh caused a crash. Now a FEM_MESH_ERROR is raised.
• Doc fixes.

All solvers with an initial data field

• Considering a computation near a data_type::initial (assumed equilibrated) displacement solution (such as a modal vibration analysis near an initial solution) and a non-linear model. The initial solution could have been the result of a previous (static) analysis with thermal stresses. In such a case, the solvers didn’t take into account the thermal stresses used to compute the initial solution.
  This non-equilibrated initial solution led to invalid results (in the cases of non-linear models).
  All these solvers are now equipped with a new data_type::initial_stress field. The initial state now takes into account the data_type::initial displacement vector and this new data_type::initial_stress.

solver_modal_gyroscopic

• Fatal errors with out-of-core management (CM2_SYSTEM_MEMORY_ERROR or crash).
• Erroneous data_type::G_requested_memory upon exit (was always equal to data_type::M_requested_memory).
• Erroneous data_type::G_assemble_time upon exit (was always equal to data_type::M_assemble_time).

All solvers

• Type operating_mode_type renamed settings_type.
• Field mode renamed settings.
• data_type::K_assemble_time (and similar) renamed data_type::K_assembly_time.

solver_Newmark_linear

• solver_Newmark_linear renamed solver_Newmark as it now allows updates of the stiffness matrix (useful only in the non-linear cases).
  See below.

solver_static_Newton

• New parameters for the watch_handler_type:
  • double E_energy (current elastic energy).
  • double P_energy (current potential energy).
  • double duNorm (max norm of the increment solution).
  • double fNorm (max norm of the residual).
  • double dE (change of elastic energy).

FEM_matrix, FEM_Zmatrix

• Parameter the_DOFs_mgr removed from members get_vector and get_vectors (was not used indeed).

Miscellaneous

• The default number of threads for each CM2 solver is now set to the number of _physical_ processors, or the omp_get_max_threads value whatever the lowest.
  See cm2::context::set_max_threads.