The ; keyword

The keyword ; is not documented yet

The @Author keyword

The @Author keyword is used to give the name of the person who wrote the mfront file.

All the following words are appended to the author’s name up to a final semicolon.

Note: The name of the person who formulated the material property, behaviour or model shall be given in the description section (see the @Description keyword).

Example

@Author Éric Brunon;

The @Bounds keyword

The @Bounds keyword let the user define the domain of validity of the law.

The @Bounds keyword is followed by a variable name, the keyword in and an interval. The interval may contain the infinity, represented by the ’*’ character.

Effect

What happens if a variable is found to be out of its bounds depends on the interface used. Most interfaces let the user choose one of three following policies:

Example

@Bounds T in [293.15:873.15];

The @Constant keyword

The @Constant keyword let the user define a constant value. This keyword is a synonym of @StaticVariable for a real variable.

This keyword must be followed by the name of the constant and its value.

Example

@Constant A 1.234e56;

The @DSL keyword

The @DSL keyword specify the domain specific language (dsl) used.

The list of available dsl’s is returned by the --list-dsl option of mfront:

$ mfront --list-dsl

As the time of writing this notice, the following dsl’s are available:

DSL options

A DSL’s behaviour may be changed using options defined either in the MFront file using a JSON-like syntax or as a command line argument.

The options related to a specific DSL can be retrieved using the --list-dsl-options command line argument, as follows:

$ mfront --list-dsl-options=Model
- parameters_as_static_variables: boolean stating if the parameter shall be treated as static variables.
- build_identifier              : string specifying a build identifier. This option shall only be specified on the command line.

Defining DSL options in the MFront file

Options can be passed to a DSL as follows:

@DSL Default{
  parameters_as_static_variables : true
};

Defining DSL options on the command line:

MFront have various command line arguments to define options passed to DSLs:

For example, the --dsl-option can be used as follows:

$ mfront --obuild --interface=cyrano --dsl-option=build_identifier:\"Cyrano-3.2\" Elasticity.mfront

This example illustrates that special care must be taken when defining an option expecting a string value.

Options common to all DSLs

The following options are available for all DSLs:

Example

@DSL Implicit;

The @Date keyword

The @Date keyword allows the user to precise when the mfront file was written.

All the following words are appended to the date up to a final semicolon.

Example

@Date 2008-11-17;

The @Description keyword

The @Description describes the material property, behaviour or model which is implemented in a mfront file.

This keyword is followed by a block containing all the relevant piece of information including:

Example

@Description
{
  Corrélation établie sur la nuance V-4Cr-4Ti.

  Propriétés extraites du document :

  Propriétés et comportement mécanique d alliages
   de Vanadium avant, après et sous irradiation

  Marion Le Flem, Jean-Luc Bechade, Annick Bougault,
  Aurore Michaux, Lionel Gosmain, Jean-Louis Seran
  DMN/SRMA/LA2M/NT/2008-2967/A
}

The @Function keyword

The @Function keyword introduces the C++ code computing the value the material property.

Note: the default output is called res. This is changed by the @Output keyword.

Note

Although most interfaces use double for floating point operations, this may not be always the case. A special typedef named real is thus introduced by the interfaces. We advise the user to use this typedef to define their local variables.

Example

@Function
{
  const real C0 =    575.57;
  const real C1 = -21094.;
  Cp = C0+C1/T;
}

The @Import keyword

The @Import keyword allows the inclusion of one or several (external) mfront files. This keyword is followed by a string or an array of strings. Each string stands for a mfront file name that is meant to be imported.

This instruction interrupts the treatment of the current file and starts the sequential treatment of each file to be imported.

Search paths

Files to be imported are searched, in that order:

Example

@Import "SlidingSystemsCC.mfront";

The @Includes keyword

The @Includes introduces a block were the user may define some preprocessor directives, typically #include directives (hence the name).

Example

@Includes{
#include<fstream>
}

The @Input keyword

The @Input keyword specifies one or several inputs of a material law. This keyword is followed by the names of the inputs, separated by commas.

The following characters are legal as the first character of an identifier, or any subsequent character:

_ a b c d e f g h i j k l m n o p q r s t u v w x y z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

The following characters are legal as any character in an identifier except the first:

0 1 2 3 4 5 6 7 8 9

External name

It is recommended to associate to an input a glossary or an entry name through the methods setGlossaryName or setEntryName respectively.

Example

@Input T,p;
T.setGlossaryName("Temperature");
p.setGlossaryName("Porosity");

The @Interface keyword

The @Interface keyword let the user specify interfaces to be used. The keyword is followed by a list of interface name, separated by commas.

Using this keyword is considered a bad practice. The user shall use the --interface command line argument to specify which interface shall be used.

Example

@Interface castem;

The @Law keyword

The @Law keyword allows the user to associate a name to the material law being treated. This keyword is followed by a name.

This name must be a valid C++ identifier. The following characters are legal as the first character of an identifier, or any subsequent character:

_ a b c d e f g h i j k l m n o p q r s t u v w x y z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

The following characters are legal as any character in an identifier except the first:

0 1 2 3 4 5 6 7 8 9

Name of the generated functions or classes

The names of the generated functions or classes depend on the law name as specified with the @Law keyword but may also include the material name, as specified by the @MaterialLaw keyword.

Example

@Law ThermalExansionCoefficient_SRMA;

The @Library keyword

The @Library keyword let the user specify part of the generated library name. This keyword is followed by the name of library.

This name must be a valid C++ identifier. The following characters are legal as the first character of an identifier, or any subsequent character:

_ a b c d e f g h i j k l m n o p q r s t u v w x y z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

The following characters are legal as any character in an identifier except the first:

0 1 2 3 4 5 6 7 8 9

Example

@Library AlcyoneLibrary;

The @Link keyword

The @Link keyword let the user specify additional linker flags used to build their shared library/executables. This keyword must be followed by a string or an array of strings.

Usage of the @Link keyword is deprecated a linker flags are not portable. The user may prefer using the LDFLAGS environment variable.

Example

// explicit link with libm.so
// (not necessary in pratice)
@Link "-lm";

The @MFront keyword

The @MFront keyword leads to the generation of sources from some mfront files as a subprocess of the current file treatment. This keyword is followed by a pair of strings or array of strings. The first member of the pair describes which a list of files to be treated. The second member of the pair describes a list of interfaces.

Example

@MFront {"YoungModulus.mfront",{"c","excel"}};

The @Material keyword

The @Material keyword let the user specify which material is treated by the current file. This keyword is followed by the name of the material.

This name must be a valid C++ identifier. The following characters are legal as the first character of an identifier, or any subsequent character:

_ a b c d e f g h i j k l m n o p q r s t u v w x y z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

The following characters are legal as any character in an identifier except the first:

0 1 2 3 4 5 6 7 8 9

Example

@Material UO2;

The @MaterialLaw keyword

The @MaterialLaw keyword imports the definition of a material law defined in a mfront file and compiles, as part of the current library, a function using the mfront interface. This function is available in every standard code blocks.

The @MaterialLaw keyword is followed by a string or an array of string identifying mfront files.

Search paths

Files to be imported are searched, in that order:

Note

The mfront interface has been created to avoid names conflict.

For internal reasons, mfront reports the creation of an auxiliary library which is of no use.

Example

@MaterialLaw "UO2_YoungModulus.mfront";

The @Output keyword

The Output keyword changes the name of the output variable. By default, this name is res. This keyword is followed by the new name of the output variable.

Example

@Output b ;

The @Parameter keyword

The @Parameter keyword declares a new parameter or a list of new parameters. Optionally, the default value of the declared parameters may also be given following various C++ standard assignment syntaxes.

The default value of a parameter can also be declared after its declaration using the setDefaultValue method.

Example

@Parameter  R0 = 500;
@Parameter  Q1{1000000000},b1{0.000001};
@Parameter  Q2(0),b2(0);
@Parameter  fc;
fc.setDefaultValue(1.e-2);

The @Parser keyword

The @Paser keyword is a deprecated synonymous of @DSL.

The @PhysicalBounds keyword

The @PhysicalBounds keyword let the use define the physical domain of a variable.

The @PhysicalBounds keyword is followed by a variable name, the keyword in and an interval. The interval may contain the infinity, represented by the ’*’ character.

Effect

In implicit schemes, if physical bounds are set on an integration variable, this variable is bounded to satisfy them during the internal iterations.

If a variable is found to be out of its physical bounds, the computations are stopped. The tests are performed at different stages of the integration depending on the nature of the variable.

Example

// a temperature (in Kelvin) can't be negative
@PhysicalBounds T in [0:*[;

The @StateVariable keyword

The StateVariable keyword introduces one or several new state variables. It is followed by a type name and the name(s) of the variable(s) declared, separated by commas.

The state variables names must be valid C++ identifiers.

The following characters are legal as the first character of an identifier, or any subsequent character:

_ a b c d e f g h i j k l m n o p q r s t u v w x y z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

The following characters are legal as any character in an identifier except the first:

0 1 2 3 4 5 6 7 8 9

Arrays

One may declare an array of state variables by specifying the array size after the state variable name.

External names

It is recommended to associate to a state variable a glossary or an entry name through the methods setGlossaryName or setEntryName respectively.

Example

// scalar state variable
@StateVariables strain p;
// symmetric tensors state variable
@StateVariables StrainStensor evp,evp2;

The @StaticVar keyword

The @StaticVar keyword is a deprecated synonymous of @StaticVariable.

The @StaticVariable keyword

The @StaticVariable keyword let the user define a constant value. Unlike parameters (see the @Parameter keyword), static variables’ values can’t be changed after compilation.

This keyword must be followed by the type of the constant, its name, an equal sign and its value.

Example

@StaticVariable real A = 1.234e56;

The @UnitSystem keyword

The @UnitSystem keyword declares that the state variables, external state variables and parameters are expressed in a given unit system. In the current version of MFront, the only supported unit system is the international system of units, denoted SI.

One advantage of declaring a unit system is that physical bounds of variables associated with a glossary entry can automatically be declared by MFront.

For instance the declaration of the physical bounds for the temperature and the porosity is automatic if the SI unit system is used.

Example of usage

@UnitSystem SI;

The @UseQt keyword

The UseQt keyword (use quantities) specify if the behaviour compilation should perform compile-time units checks. It is followed by a boolean.

Note

This feature is still experimental and is disabled in most cases.

Example

@UseQt true;