**NAME**

line

**SYNOPSIS**

line x1 y1 x2 y2 [-optional link arguments]

**DESCRIPTION**

linecreates a straight line entity of immersed boundary points.linerequires four arguments.

- x1 -
xcoordinate of the line endpoint (x1,y1)- y1 -
ycoordinate of the line endpoint (x1,y1)- x2 -
xcoordinate of the line endpoint (x2,y2)- y2 -
ycoordinate of the line endpoint (x2,y2)lineallows for optional link arguments by interpreting the following options.

- -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 =x_{min},x2 =x_{max}andy1 =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 tox1 and the net effect will be minimal. Lines in the ``y'' direction cannot be periodic.

**SEE ALSO**

tube,itube,polygon-ray

**EXAMPLE**

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.