line x1 y1 x2 y2 [-optional link arguments]
line creates a straight line entity of immersed boundary points. line requires four arguments.
line allows for optional link arguments by interpreting the following options.
- x1 - x coordinate of the line endpoint (x1,y1)
- y1 - y coordinate of the line endpoint (x1,y1)
- x2 - x coordinate of the line endpoint (x2,y2)
- y2 - y coordinate of the line endpoint (x2,y2)
- -A name - indicates this entity is active and provides a name
- -a angle - resting angle at the IB points (default=0)
- -b bend - bending stiffness at the IB points (default=40000)
- -d distance - initial distance between IB points (default=0.5)
- -N name - provides a name for the entity
- -n number - number of IB points on the line segment
- -s stiff - inter-IB-point spring stiffness (default=40000)
- -t tether - tether spring stiffness (default=0)
If the x1 = xmin, x2 = xmax and y1 = y2, the line is assumed to be periodic. In this case, forces are calculated between the endpoints of the line after it has been wrapped periodically. If this is not desired, the add a small amount to x1 and the net effect will be minimal. Lines in the ``y'' direction cannot be periodic.
tube, itube, polygon-ray
line 0 0 1 2 -t 10000.0
Sets a line running from (0,0) to (1,2) and tethers the the line with springs whose stiffness is 10000.