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File Formats


OFELI data files use the XML syntax. They are valid XML documents. Input files can be given separately or gathered in one or more files.

A typical set of header lines of OFELI XML files is the following lines:

     <?xml version="1.0" encoding="ISO-8859-1" ?>
     <OFELI_File>
     <info>
        <title></title>
        <date></date>
        <author></author>
     </info>
     ...
     ...
     </OFELI_File>
Tags title, date and author can be filled in order to keep useful information for a user.
After the preamble given by the element <info>, the XML file can contain any of the following elements in any order:

Project

To describe project data: parameters, input and output files, ... This information enables constructing the class IPF.

Domain

To describe domain geometry

Mesh

To describe mesh data

Prescription

To describe prescription of boundary conditions, body and boundary forces, ...

Material

To describe material data

Field

To describe input and output field data

Function

To describe a tabulated function
     

Element: Project

The element Project enables giving various parameters to control program execution as well as various file names. All acquired data are used to construct the class IPF. When invoking this element, one must supply the attribute that gives the projects name as follows:

     
     <Project name="project_name">
        ...
        ...
     </Project>

The element Project has a large choice of subelements. Each subelement is a parameter that can be retrieved by calling a member function of class IPF. These parameters either have a predefined name, e.g. max_time that clearly chooses the maximal time for computations and whose is retrieved in the class IPF by the member function getMaxTime, or by a generic parameter for which a user can define a label. For instance, in the line

     <parameter label="deltat" value="0.1"&/>
the read parameter is retrieved by the code line
     dt = ipf.getDouble("deltat");
or equivalently
     ipf.get("deltat",dt);
where ipf is an instance of class IPF.

The following table describes the list of parameters in the Prescription file:


verbose

Level for information output. Typically, the integer number must be between 1 and 10. Its default value is 1

output

Level for solution output. Its default value is 0

save

Level for solution saving in file. Its default value is 0

plot

An integer that defines a level for solution saving in plot file. Its default value is 0

bc

Flag for boundary condition (Dirichlet) handling.
1: Boundary condition vector is described in a prescription file (Default value)
2: Boundary condition vector is in a field file

bf

Flag for body force handling.
1: Body force is described in a prescription file (Default value)
2: Body force vector is in a field file

sf

Flag for surface force (Neumann boundary condition) handling.
1: Surface force vector in a prescription file (Default value)
2: Read surface force vector in a field file

init

Flag for initial condition handling.
1: Initial solution in a prescription file (Default value)
2: Read initial solution in a field file

max_time

A real number that defines maximal time for a time dependent calculation. Its default value is 1.0

time_step

Time step for a time dependent calculation. Its default value is 0.1

nb_steps

Number of time steps for a time dependent calculation. Its default value is 10

nb_iter

Maximum number of iterations for an iterative scheme. Its default value is 100

tolerance

Tolerance for convergence for an iterative scheme. Its default value is 1.e-6

integer

An integer parameter that can be retrieved by the member function getIntPar(i) where i is the rank of appearance of this keyword. Up to 10 integer parameters can be contained in the file. This maximal number is defined by the constant MAX_NB_PAR in the constants

double

A double precision parameter that can be retrieved by the member function getDoublePar(i) where i is the rank of appearance of this keyword. Up to 10 double precision parameters can be contained in the file. This maximal number is defined by the constant MAX_NB_PAR in the constants

complex

A complex parameter that can be retrieved by the member function getComplexPar(i) where i is the rank of appearance of this keyword. Up to 10 complex parameters can be contained in the file. This maximal number is defined by the constant MAX_NB_PAR in the constants

mesh_file

Name of file that contains mesh data. The default mesh file name has as extension project_name.m

init_file

Name of file that contains initial data

restart_file

Name of file that contains restarting field file. This file is useful when an iteration process (or time stepping procedure) is used and the programs stops to restart later

bc_file

Name of file that contains (Dirichlet) boundary condition data

bf_file

Name of file that contains body force initial data

sf_file

Name of file that contains surface force data

save_file

Name of file that fields to save

plot_file

Name of file that contains fields to plot

data_file

Name of file that contains various data

aux_file

Name of file that contains any other data in any format. Any occurrence of this keyword will define a new file name that can be retrieved through the member function getAuxFile(i) where i is the rank of the appearance of this keyword. Up to 10 occurrences can be contained in the file. This maximal number is defined by the constant MAX_NB_PAR in the constants

parameter

As explained in the example above, this subelement must contain an option called label that identifies the parameters and then optionally the option value to specify a value. If this option is not present, a value must be given before closing the subelement

Note that the argument of each subelement can be given either through the attribute value or through a value that given between the opening and the closing of the subelement.

Let us give a simple example of XML file using the Project element, where we have used both possibilities of defining subelements.

     <?xml version="1.0" encoding="ISO-8859-1" ?>
     <OFELI_File>
     <info>
        <title>Project file</title>
        <date>August 18, 2008</date>
        <author>R. Touzani</author>
     </info>
     <Project name="beam">
        <mesh_file>beam.m</mesh_file>
        <data_file>beam.pr</data_file>
        <parameter label="d-file">beam.d</parameter>
        <parameter label="density" value="1.2"/>
        <nb_iter>100</nb_iter>
        <tolerance value="1.e-5"></tolerance>
        <verbose>1</verbose>
        <output>1</output>
        <save value="1"/>
     </Project>
     </OFELI_File>
    

Element: Domain

The element Domain enables defining a domain geometry. At the current stage of development of , a domain definition is necessary to generate meshes in the 2-D configurations. This element has 2 attributes: An example of use of this element is:
     <Domain dim="2">
        <vertex>  0.   0.   1    0.1</vertex>
        <vertex>  1.   0.   1    0.1</vertex>
        <vertex>  1.   1.   1    0.1</vertex>
        <vertex>  0.   1.   1    0.1</vertex>
        <vertex>  0.5  0.5  2    0.1</vertex>
        <vertex>  0.6  0.5  2    0.1</vertex>
        <line>   1   2   1</line>
        <line>   2   3   1</line>
        <line>   3   4  -2</line>
        <line>   4   1  -2</line>
        <circle> 6   6   5   1</circle>
        <subdomain>   1   1  10</subdomain>
     </Domain>
Let us describe the subelements of element Domain:


vertex

To describe a vertex in the domain

line

To describe a straight line that joins 2 vertices

circle

To describe a circular arc

subdomain

To describe a subdomain with a specific code

   

Element: Mesh

The element Mesh enables providing data that describe a finite element mesh. It has 2 optional attributes: An example of use of this element is:
     <Mesh dim="3" nb_dof="2">
        ...
        ...
     </Mesh>
This element has the following subelements:

Nodes

To describe nodes

Elements

To describe elements

Sides

To describe sides

Material

To describe materials for elements

    

Element: Prescription

This element encloses information on conditions to prescribe for the numerical solution by the library. We mean here by prescription, enforcement of boundary conditions (Dirichlet), Boundary forces (Neumann boundary conditions, Body forces (right-hand side of equations, initial condition, ... To each type of prescription corresponds a subelement. Moreover, prescription of variable (time and/or space dependent) conditions are allowable through algebraic equations.
The element Prescription doesn't have any attribute. It has the following subelements:

BoundaryCondition

To prescribe (essential or Dirichlet) boundary conditions

BodyForce

To prescribe body forces or sources, ...

Source

Identical to BodyForce

BoundaryForce

To prescribe boundary forces (Neumann boundary conditions), like tractions, fluxes, ...

Traction

Identical to BoundaryForce

Flux

Identical to BoundaryForce

Initial

To prescribe an initial condition

    

Element: Material

Material data are stored in specific XML files. Each file corresponds to a given material. The library contains a collection of material files that will be enriched in the forthcoming releases.
In , the material named Mat is described in the XML file: Mat.md

Let us give as example the material file for the material Copper. Here is the listing of the file Copper.md the

     <?xml version="1.0" encoding="ISO-8859-1" ?>
     <OFELI_File>
     <info>
        <title>Material data for Copper</title>
        <date></date>
        <author></author>
     </info>
     <Material name="Copper">
        <Density>1.</Density>
        <SpecificHeat>8920.</SpecificHeat>
        <ThermalConductivity>401.</ThermalConductivity>
        <ElectricConductivity>5.9302e07</ElectricConductivity>
        <ElectricResistivity>1.6863e-8</ElectricResistivity>
        <MagneticPermeability>12.566371e-7</MagneticPermeability>
        <PoissonRatio>0.34</PoissonRatio>
        <YoungModulus>15.e10</YoungModulus>
     </Material>
     </OFELI_File>

The structure of this file doesn't need any additional explanation. We shall however give hereafter the list of properties that can be stored in the XML file:

Density

Density of material (Heat and Mass Transfer)

SpecificHeat

Specific Heat (Heat Transfer)

ThermalConductivity

Thermal Conductivity (Heat Transfer)

MeltingTemperature

Melting Temperature (Heat Transfer)

EvaporationTemperature

Evaporation Temperature (Heat Transfer)

ThermalExpansion

Thermal Expansion (Heat and Mass Transfer)

LatentHeatMelting

Latent Heat for Melting (Heat Transfer)

LatentHeatEvaporation

Latent Heat for Evaporation (Heat Transfer)

DielectricConstant

Dielectric Constant (Electromagnetism)

ElectricConductivity

Electric Conductivity (Electromagnetism)

ElectricResistivity

Electric Resistivity: Inverse of Conductivity (Electromagnetism)

MagneticPermeability

Magnetic Permeability (Electromagnetism)

Viscosity

Kinematic Viscosity (Fuid Dynamics)

YoungModulus

Young Modulus (Solid Mechanics)

PoissonRatio

Poisson Ratio (Solid Mechanics)
    

Element: Field

The element Field is useful to store vectors, such as input vectors, results. We have grouped all these vectors under the term Field. The field file that contains these vectors can be transformed via conversion programs to various file formats for well known free and commercial graphical postprocessors.

Fields can be divided into 3 types depending on the degree of freedom support: Fields can be given by nodes, elements or sides. In addition, in view of handling time-dependent problems, the file can contain as many vectors as necessary, each one corresponding to a given time step.

A typical file containing fields looks like this

     
     <OFELI_File>
        ... ...
     <Field name="Temperature" type="Node" nb_dof="1">
        <Step time="0.1">
          ... ...
          ... ...
        </Step>
        <Step time="0.2">
          ... ...
          ... ...
        </Step>
     </Field>
     <Field name="Displacement" type="Element" nb_dof="2">
        <Step time="0.1">
           <constant dof="1">1.0</constant>
           <expression dof="2">x*exp(t)</expression>
        </Step>
     </Field>
     </OFELI_File>

More precisely, the element Field has the attributes:     

Element: Function

The element Function defines a tabulated function of one, two or three variables. In order to minimize computational cost, each variable is defined by a uniform partitioning given by its minimal value, its maximal values and the number of grid points.
This element has as unique attribute the name of the function.
A typical usage of this element is:
     <Function name="Density">
        <Variable label="x" nb_pts="5" min="0" max="1"/>
        <Variable label="y" nb_pts="4" min="10" max="12"/>
        <Data>
           1.0   2.0   5.0   7.0
           2.0   3.0   5.0   8.0
           7.0   2.0   5.0   9.0
           0.0   2.0   8.0  10.0
          11.0  20.0  25.0  30.0
        </Data>
     </Function>
Let us describe the subelements of element Function:

Variable

To describe a variable

Data

To give list of function values

 
Copyright © 1998-2017 Rachid Touzani