easifemClasses

The easifemClasses (henceforth, the Classes) library, forms the second level of EASIFEM library. This library contains many useful high-level objects, which are important for implementing FEM. The main programming paradigm of Classes library is object-oriented programming.

Use association

USE easifemClasses

Installation

Before installing the Classes library please install:

• requirements
• external pkgs
• base library.

EASIFEM cli (recommended method)

Step-1: Install the easifem command line application by using:

python3 -m pip install --upgrade easifem

Step-2: Set the environment variables by specifying the src, build, and install directory as shown below:

easifem setenv --install <install directory> --build <build directory> --source <source directory>
source ~/.config/easifem/easifemvar.sh

You can find detailed information here.

Step-3: If you have not installed the extpkgs, then you can install them by running:

easifem install extpkgs

Step-4: Now, you can install the Base library by:

easifem install base

Step-5: Now, you can install the Classes library by:

easifem install classes

note

You can combine step-3 to step-5 by using:

easifem install extpkgs base classes

CMake

Download the source code:

git clone https://github.com/vickysharma0812/easifem-classes.git

or

git clone git@github.com:vickysharma0812/easifem-classes.git

or

gh repo clone vickysharma0812/easifem-classes

After downloading the source code, enter the source directory, and make a build directory.

cd easifem-classes
mkdir ./build

EASIFEM uses CMake build system. You can install the Base library from CMake by using following steps

1. Configuration
2. Build
3. Install

To configure the Base library you can define following variables:

Variable	Type	Options
USE_OpenMP	BOOL	ON, OFF
CMAKE_BUILD_TYPE	STRING	Release, Debug
BUILD_SHARED_LIBS	BOOL	ON, OFF
CMAKE_INSTALL_PREFIX	PATH
USE_GMSH_SDK	BOOL	ON, OFF

An example of configuration step is given below:

export EASIFEM_CLASSES=${HOME}/.local/easifem/classes
cmake -G "Ninja" -S ./ -B ./build \
-D USE_OpenMP:BOOL=ON \
-D CMAKE_BUILD_TYPE:STRING=Release \
-D BUILD_SHARED_LIBS:BOOL=ON \
-D CMAKE_INSTALL_PREFIX:PATH=${EASIFEM_CLASSES} \
-D USE_GMSH_SDK:BOOL=ON

After configuration, you can build and install the library by using:

cmake --build ./build --target --install

Structure

Similar to the Base library, the Classes library has two directories in the src directory:

1. modules
2. submodules

The modules directory mainly contains following items:

1. Type definition including methods
2. Header and interface of methods

The 📁submodules directory contains the implementation of the methods that are defined in the modules directory.

• In addition, each class has its own subdirectory in the modules and submodules directory.
• For example, the directory of Domain_ class is Domain, the directory of Mesh_ class is Mesh.
• In this way, modules/Domain will define the Domain_ class and interface of methods, whereas submodules/Domain will include the submodules that implementes the methods defined inside modules.
• The name of the module which defines Domain_ class is Domain_Classs, and it is included in the file called Domain_Class.F90.
• The submodule, which defines methods (for example, constructor methods) will be included in Domain_Class@ConstructorMethods.F90, Domain_Class@IOMethods, etc.

info

If you want to implement a class called XXX_, then perform following task:

1. Make a subdirectory XXX in src/modules and src/submodules
2. In both XXX make a subdirectory XXX/src
3. Create a file modules/XXX/src/XXX_Class.F90 and define a module called XXX_Class:
4. Create submodules in submodule/XXX/src/XXX_Class@CategoryofMethods.F90 and implement the methods.

MODULE XXX_Class
!! Use modules
PRIVATE
!!  Define class here
END MODULE XXX_Class 

Modules

easifemClasses currently contains following modules:

Module	Comment	Category
Gmsh_Class	Interface to Gmsh library	Mesh
CommandLine_Method	Fortran library for making comand line applications.	CLI
ExceptionHandling_Class	Fortran library for error handling	Utility
FPL_Method	Fortran parameter list	FEM
Files	Collection of modules related to File IO.	IO
ElementFactory	Finite element factory	FEM
IntList_Class	Linked list of integers	Container
RealList_Class	Linked list of reals	Container
StringList_Class	Linked list of strings	Container
ElementList_Class	Linked list of finite elements	FEM
ElementPointerVector_Class	Dynamic vector of element pointers	FEM
Mesh_Class	Finite element mesh class	FEM
MeshPointerVector_Class	Dynamic vector of mesh pointers	FEM
Domain_Class	Domain class	FEM
DomainUtility	A module for additional methods on Domain.	FEM
DomainConnectivity_Class	Domain connectivity class	FEM
MeshSelection_Class	A class for selecting the region of domain.	FEM
MSHFile_Class	Class for Gmsh`s msh file	FEM
AbstractVector_Class	Abstract class for vectors.	FEM
Vector_Class	Concrete class for vectors.	FEM
Field	Collection of modules which defines classes for finite element fields.	FEM
FieldFactory	Factory for fields	FEM
AbstractLinSolver_Class	Abstract class for linear solver	FEM
LinSolver_Class	Native linear solver class.	FEM
LinSolver_Factory	Factory for linear solvers.	FEM
AbstractBC_Class	Abstract class for boundary conditions	FEM
DirichletBC_Class	Class for Dirichlet boundary conditions.	FEM
NeumannBC_Class	Class for Neumann boundary conditions.	FEM
NitscheBC_Class	Class for Nitsche boundary conditions.	FEM
PolynomialFactory	Factory of polynomials	FEM
UserFunction_Class	User function class	FEM
RefElementFactory	Factory of reference elements	FEM
FiniteElementFactory	Factory of finite elements.	FEM
Tree3R_Class	Tree data structure for 3 term recurrence relation.	Math
Plot_Method	Collection of methods for plotting.	FEM