Initializers

Topics
	Scalar initializers
	Vector initializers
	Shape initializers

Classes
interface	type_initializer::scalar_initializer_get_scalar
	Evaluate the initializer at a point to get a scalar value. More...

Detailed Description

Introduction

Basic initializers

An initializer is a structure that contains a set of instructions to initialize a given field. It is a direct representation in Fortran of the INITIALIZERs of the NTS files. There a 3 kinds of initializers:

• Scalar initializers (SCALAR_INITIALIZER in NTS files). They contains a set of instructions to initialize scalar fields.

  Scalar initializers must inherit an abstract class type_initializer::t_scalar_initializer and they must provide a get_scalar type-bound procedure. This abstract class is recursive. It contains a pointer to the next scalar initializer.

• Vector initializers (VECTOR_INITIALIZER in NTS files). They contains a set of instructions to initialize vector fields.

  Vector initializers must inherit an abstract class type_initializer::t_vector_initializer and they must provide a get_vector type-bound procedure. This abstract class is recursive. It contains a pointer to the next vector initializer.

• Shape initializers (SHAPE_INITIALIZER in NTS files). They contains a shape to initialize a geometric field.

  Shape initializers are of class type_initializer::t_vector_initializer that contains 3 type-bound procedures: is_inside, get_samples_inside and get_distance. As opposed to scalar and vector initializer, this class is not recursive.

Example

Consider the initialization of a scalar field (e.g. the temperature) in an NTS file:

initial_condition {
   constant 1.0;
   shape 2.0 {
      circle {center (0.0, 0.0); radius 0.5;}
   }
}

The NTS parser will translate these instructions into the following structure:

┌───────────────────────────────┐      ┌────────────────────────────┐
│ t_scalar_initializer_constant │      │ t_scalar_initializer_shape │
│  → scalar = 1.0               │      │  → scalar = 1.0            │
│  → next ---------------------------→ │  → shape = (circle)        │
└───────────────────────────────┘      │  → next (not associated)   │
                                       └────────────────────────────┘

The constant 1.0 is translated into an object of class type_initializer::t_scalar_initializer_constant that contains an item scalar with value equal to 1.0. This object contains a item which corresponds to the next initializer. This initializer is a constant scalar value in a shape. It is described as an object of class type_initializer::t_scalar_initializer_shape.

Implementation details

The scalar and vector initializers are organized as follow. TYPE denotes either scalar or vector.

t_TYPE_initializer
├ t_TYPE_initializer_constant              [attributes: TYPE]
│ └ t_TYPE_initializer_shape               [attributes: TYPE, shape]
└ t_TYPE_initializer_instructions          [attributes: instruction]
  └ t_TYPE_initializer_shaped_instructions [attributes: instruction, shape]