# created: 20.07.2007 (-1)
# last revision: 20.07.2009 (+1)

from 2009.2 to 2009.3
=====================
- basic support for Windows installation via numpy distutils (finally!):
  - installation using standard "python setup.py install"...
- postproc.py:
  - quite usable now for fast first glance at the results
  - plots point, cell data of all kinds (scalar, vector, tensor)
  - draw iso-surface in 3D mode
  - fixed filename in Viewer for femhub notebook
  - new options: --scalar-mode, --list-names, --only-names,
    --rel-text-width, --no-show, --roll, --view, --all, --layout, -o
- cylindergen.py:
  - cylindrical mesh generator
- probe.py:
  - can probe selected quantities only
  - new options: --only-names, --auto-dir, --same-dir
- isfepy:
  - new options: --no-wx, --no-viewer
- phono: basic support for liquid inclusions
  - support for inner band gaps detection (brute force) and plotting
- homogenization: added new-style piezo-elastic corrector and coefficient classes
- schroedinger: fixed charge density computation
- solvers:
  - added SciPy direct sparse solvers (ls.scipy_direct) - unified
  umfpack, superlu
- new terms:
  - de_grad (element average of gradient)
  - d_volume_surface (compute volume using surface integral)
  - dw_bc_newton (Newton boundary condition)
  - dq_state_in_volume_qp, dq_state_in_surface_qp (interpolating state
    into quadrature points)
  - dw_surface_integrate_variable (weak surface term with variable coefficient)

from 2009.1 to 2009.2:
======================
- scripts:
  - added probe.py - a script to probe and plot results saved in result files
    - data probes along geometrical objects (e.g. lines, rays) intersecting the
      mesh
  - added postproc.py - a script to visualize results saved in result files
    - added Viewer class - 3D plots using mayavi2
    - rudimentary automatic mode only
  - added isfepy (interactive sfepy) IPython shell
    - uses new pde_solve(), pre-imports mayavi2 based Viewer
- short input syntax for LCBC conditions, fields, integrals, materials and
  solvers
- automatic html documentation generation via doxygen
- new mesh readers:
  - Nastran (.bdf) format
  - Abaqus ascii (.inp)
- new example problems:
  - subdomains.py + test - test dw_jump interface term
  - stabilized_navier_stokes.py input + test - test Oseen solver
  - acoustics.py + test - compute complex acoustic pressure
- solvers:
  - changed API of nonlinear solvers so that scipy solvers can be used
  - added Broyden and Anderson nonlinear solvers (SciPy implementation)
  - updated Oseen solver 
- major rewrite of handling of dof connectivities, matrix graph and term
  geometries:
  - lots of dof connectivity related code was simplified/removed
  - extra connectivity data (surface, point) computed on demand in
    Variables.setup_dof_conns()
  - support for terms with traces of variables on interface regions
  - surface data computation for terms of volume dof_conn and Surface geometry
- extended syntax of equations to allow boundary traces of variables:
  - to use when a field value at an interface boundary is needed from the
    neighbouring subdomain side and the field is not defined there
  - example: dw_jump.isurf.Gamma12_1( jump1.val, q1, p1, tr(p2) )
- refactored linear combination boundary conditions (LCBC) code:
  - fixed rigid LCBC for multi-field problems
  - added no penetration LCBC
  - major speed-up (several orders) of LCBC operator construction
    - assembled via the coo_matrix instead of the lil_matrix
  - fixed check_tangent_matrix() for LCBC
- applications:
  - homogenization:
    - prefactorize the matrix for linear corrector problems - major speed-up
  - phononic materials:
    - plot also middle eigenvalues in 3D, fixed plot labels, polarization angles
    - caching of eigenvalue problem solution and Christoffel acoustic tensor
  - schroedinger.py:
    - choose and call DFT solver via solver interface
- general:
  - fixed boundary quadrature points for multi-field problems
  - fixed complex assembling
  - fixed live plotting (ProcessPlotter) for multi-core machines
  - improved Output class, simplified its usage
  - Struct.__str__() prints in alphabetical order
  - unified version information by introducing sfepy.__version__
  - polished MeshIO class
  - implemented region selection by node groups
  - refactored Mesh nodes, lots of simplifications
  - many small fixes and updates
- new terms:
    - dw_jump (scalar interface jump term)
    - dw_surface_mass_scalar (scalar mass on a surface boundary)

from 2008.4 to 2009.1:
======================
- new solvers:
  - simple backtracking steepest descent optimization solver
  - PETSc Krylov solvers via petsc4py, sequential mode
  - LOBPCG eigenvalue solver (SciPy implementation)
- new mesh readers:
   - mesh3d (hermes3d)
   - AVS UCD ascii mesh
   - Hypermesh ascii mesh
- homogenization: 
  - MiniAppBase base class for "mini-applications": micro-problem correctors,
    homogenized coefficients
  - unified approach to resolve data dependencies: HomogenizationEngine class
- applications:
    - phononic materials:
      - dispersion analysis, phase velocity computation for phononic materials
      - homogenized coefficients computed via the HomogenizationEngine
      - caching of coefficients to speed up parametric runs
    - schroedinger.py:
      - all functionality moved into SchroedingerApp class
      - inherits from SimpleApp -> can be parametrized
      - fixed DFT iterations, iteration plot saving
      - basic smearing around Fermi limit
- scripts:
  - convert_mesh.py:
    - --scale option, support different scaling for each axis
- general:
  - terms, caches now imported dynamically by load_classes()
    - to add a new term/cache module just put it into sfepy/terms/
  - better setup of Application options
    - automatic option update in parametric studies
  - default configuration options for the linear, nonlinear and eigen- solvers
  - various 64bit fixes
  - allow empty output prefix, combined output to file and terminal
- new terms:
    - dw_electric_source (electric source term)

from 00.50.00 to 2008.4:
========================
- framework for running parametric studies
- allow time derivatives of variables as term arguments
  - example (transient diffusion):
    """dw_mass_scalar.i1.Omega( s, dT/dt )
     + dw_laplace.i1.Omega( coef.val, s, T ) = 0"""
- initial conditions via ics, ic_<number> keywords
- enhanced acoustic band gaps code
  - dispersion analysis (polarization angle calculation)
  - applied load tensor computation
  - phase velocity computation for periodic perforated media with empty holes
- term base classes
  - actual term code reduced significantly
  - adding new terms is even easier now
- type of term arguments determined fully at run-time
  - many terms were unified
  - the same term can be used both for the finite element assembling and the
  evaluation of the weak form for known fields (dw_ = d_)
- live plotting using multiprocessing module
  - assumes GTKAgg matplotlib backend
  - support for setting x axis values and labels and y labels
  - figure saving
- printing messages: Output class
- homogenized coefficients classes prototypes
- improved schroedinger.py
  - plotting DFT iterations
- created sfepy/mechanics
  - conversions of elastic constants and transformations to plane
- float format used for saving results can be set by the 'float_format' option
- new terms:
  - dw_piezo_coupling (piezo-electric coupling term)
  - dw_biot (Biot coupling term, former dw_biot_div, dw_biot_grad, ...)
  - dw_stokes (Stokes coupling term, former dw_div, dw_grad, ...)
  - dw_lin_elastic_th (linear elasticity fading memory, former dw_lin_viscous_th)
  - dw_biot_th (Biot fading memory terms unified)

from 00.46.02 to 00.50.00:
==========================
- finite strain elasticity: neo-Hookean, Mooney-Rivlin materials
  - total Lagrangian (TL) formulation
  - geometric data via finite_strain_tl DataCache
- solving problems in complex numbers
- generalized equations to allow linear combination of terms
  - example: """2 * aterm.i1.Omega( v, u ) = - 3.0 * bterm.i1.Omega2( v, u )""" 
- run-time type of state term arguments
  - removed all *_r terms, now useless
- 'elements by function( domain )' region selector
- refactoring to follow Python coding style guidelines
- history support in variables
- MeshIO.read_dimension() to quickly get dimension in an input file
- improved site_cfg_template.py
- improved schroedinger.py
- new terms:
  - de_average_variable (average a variable in elements)
  - dw_surface_integrate (integrate over surface operator)
  - dw_tl_bulk_penalty (bulk penalty in TL formulation)
  - dw_tl_he_neohook (neo-Hooekan term in TL formulation)
  - dw_tl_he_mooney_rivlin (Mooney-Rivlin term in TL formulation)

from 00.41.03 to 00.46.02:
==========================
- alternative short syntax for specifying essential boundary conditions,
  variables and  regions
- saving results per variable (useful when variables defined in different
  subdomains)
- manufactured solutions tests:
    - SymPy support
- new eigenvalue solvers:
    - removed symeig dependence
- linear solvers based on PyAMG
- simple block mesh generator
- unified HDF5 mesh/solution reading/writing
- site configuration now via script/config.py + site_cfg.py
- example: computing homogenized elastic coefficients
- new terms and lots of reorganization:
    - Biot terms
    - some fading memory terms

from 00.35.01 to 00.41.03:
==========================
- works on 64 bits
- support for various mesh formats:
    - medit: .mesh
    - text VTK: .vtk
    - tetgen: .node + .ele
    - comsol: .txt
- Schroedinger equation solver
    - run via 'schroedinger.py'
- input files:
    - new syntax for variables and boundary conditions
    - improved handling of degrees of freedom
- more descriptive (and less) test and simulation messages
- new handling of approximations (-> lots of thing simplified)
- material parameters can be defined in mesh vertices
- simple.py: allow user-specified postProcessHook function
- documentation generation via prettydoc
- new solvers:
    - generic time-dependent problem solver
    - pysparse, symeig, scipy-based eigenproblem solvers
    - scipy-based iterative solvers
- new terms:
    - dw_volume_integrate (volume integral operator)
    - dw_mass_scalar_r (rhs for time-dependent Poisson problem)
    - di_volume_integrate_mat (integrate material parameters)
    - dw_volume_wdot and related terms (weighted dot product)
    - dw_mass_scalar_variable (scalar mass term with variable coefficients)
    - dw_lin_elastic and related terms (anisotropic linear elasticity)
    - dw_lin_viscous (linear viscosity)
    - de_cauchy_stress (element-averaged Cauchy stress)

from 00.31.06 to 00.35.01:
==========================
- per term integration, major rewrite of sfe.fem and related:
    - term.integral.domain( arguments ) syntax
    - 'integral_*' keyword for input files
    - each term can use its own quadrature points
    - 'field' keyword syntax changed

- minor:
    - genDocs.py: PDF term documentation generator

from 00.26.01 to 00.31.06:
==========================

- acoustic band gaps determination:
    - zones of frequencies where elastic waves do not propagate
    - based on homogenization of material made of small inclusions periodically
    embedded in an elastic matrix
    - run via 'eigen.py'
- general linear combination boundary conditions - 'lcbc' keyword:
    - rigid body motion constraint imposed on regions
- new Solver classes, solver reorganization:
    - all solvers now configured in a uniform way ('solver_[0-9]+' keywords)
    - specify solvers using 'options' keyword
- new terms:
    - dot product in a volume or on a surface region
    - vector field mass term
    - scalar field "mass", fine-coarse scalar "mass" terms:
        - used for coarse mesh -> fine mesh interpolation of scalar fields

- minor:
    - added updated findSurf.py into distribution - extract surface from a mesh
    - script/kill_*
    - script/writeMesh2D.m
    - script/writeSparseMatrixHDF5.m

from 00.22.02 to 00.26.01:
==========================

- testing framework (in the spirit of unit tests):
    - particularly tests that standard input files work
    - runTests.py: output filtering
- linear spring term (kind of a relaxed Dirichlet BC on node displacements)
- volume term
- Laplace term in 2D
- chained periodic boundary conditions resolving
- new options for simple.py: --save-field-meshes, --solve-not
- periodic mesh merger (genPerMesh.py)

- minor:
    - improved region saving
    - growing term data cache
    - sparse matrix saving into HDF5
    - point dof connectivity and geometry
    - region handling improvements (canCells flag)
    - nonlinear solver status reporting
    - distribution: test and example meshes included in the release tarball