CGAL 4.14 - 2D Placement of Streamlines
VectorField_2 Concept Reference

## Definition

The concept VectorField_2 describes the set of requirements for the first template parameter of the class CGAL::Stream_lines_2<VectorField_2,Integrator_2>. This concept provides the types of the geometric primitives used in the placement of streamlines and some functions for answering different queries.

Has Models:

CGAL::Regular_grid_2<StreamLinesTraits_2>

CGAL::Triangular_field_2<StreamLinesTraits_2>

## Types

typedef unspecified_type Geom_traits
The traits class.

typedef unspecified_type FT
The scalar type.

typedef unspecified_type Point_2
The point type.

typedef unspecified_type Vector_2
The vector type.

## Creation

VectorField_2 ()
Any constructor has to allow the user to fill the vector values, i.e., assign a vector to each position within the domain.

## Query Functions

Geom_traits::Iso_rectangle_2 bbox ()
returns the bounding box of the whole domain.

std::pair< Vector_2, FTget_field (Point_2 p)
returns the vector field value and the local density. More...

bool is_in_domain (Point_2 p)
returns true if the point p is inside the domain boundaries, false otherwise.

FT get_integration_step (Point_2 p)
returns the integration step at the point p, i.e., the distance between p and the next point in the polyline. More...

## ◆ get_field()

 std::pair VectorField_2::get_field ( Point_2 p )

returns the vector field value and the local density.

Precondition
is_in_domain(p) must be true.

## ◆ get_integration_step()

 FT VectorField_2::get_integration_step ( Point_2 p )

returns the integration step at the point p, i.e., the distance between p and the next point in the polyline.

Precondition
is_in_domain(p) must be true.