StreamlinePyr

DESCRIPTION

This modules computes a streamline in a vector field defined on the base lattice of a pyramid. It requires a pick input to seed the streamline. Streamlines can be advected forwards and/or backwards in time. Any type of pyramid is allowed. Simple linear interpolation together with a second-order adaptive Runge-Kutta method is used for numerical integration.

INPUTS

Port: Pyramid In
Type: Pyramid
Constraints: 1..3-layer
Constraints: 1..-baseLat
Constraints: 1..3-D compression
Constraints: n-compression type
The pyramid whose base lattice contains the vector data.

Port: Start Point
Type: Pick
The start point of the streamline.

Port: Timestep
Type: Parameter
Optional: This port is optional.
The integration timestep can be set by wiring a parameter into this port. Otherwise, the timestep is computed internally, which may or may not be appropiate.

WIDGETS

Port: Direction
Type: Option Menu
Menu Item: Forwards
Menu Item: Backwards
Menu Item: Both
The direction (in time) to advect the particle.

Port: Clear
Type: Button
Remove all existing streamlines from the display.

OUTPUTS

Port: Streamline
Type: Geometry
The streamline.

KNOWN PROBLEMS

The streamline will terminate when it reaches a stagnation point, or exceeds a certain number of points. No checking for closed streamlines is done. The interpolation scheme is valid within a radius of the grid points. This means that streamlines may go beyond the bounds of the domain.

SEE ALSO

NAGAdvectSimple, NAGAdvectAnimate.
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© The Numerical Algorithms Group Ltd, Oxford UK. 2000