# Boundary conditions (Randbedingungen)¶

Command: def_bcond_vpo(x1, y1, x2, y2)

Tangential boundary condition

Parameter
x1,y1 Start-point coordinates
x2,y2 End-point coordinates

Command: def_bcond_vpc(x1, y1, x2, y2, vpr, vpi)

Constant vector potential

Parameter
x1,y1 Start-point coordinates
x2,y2 End-point coordinates
vpr Real part of vector potential [Vs/m]
vpi Imaginary part of vector potential [Vs/m]

Command: def_bcond(x1, y1, x2, y2, x3, y3, x4, y4, type)

Periodic boundary condition

Parameter
x/y1 Coordinates of point 1 (left, above)
x/y2 Coordinates of point 2 (left, below)
x/y3 Coordinates of point 3 (right, below)
x/y4 Coordinates of point 4 (right, above)
type Type of boundary condition. Positive periodicity: 4 (deprecated) or “pos”, negative periodicity: 3 (deprecated) oder “neg”.

Example:

```def_bcond(x1,y1,x2,y2,x3,y3,x4,y4,"neg")   -- apply a negativ periodic boundary condition
def_bcond(x1,y1,x2,y2,x3,y3,x4,y4,3)       -- deprecated version
```

Command: def_bcond_inf()

Infinity boundary condition

Command: def_bcond_int_vpo(x1, y1, x2, y2, x3, y3, ..)

Internal condition (vector potential zero) within the defined area

Parameter

xi, yi Point of the area surounding polygon

Command: def_bcond_int_vpc(vpr, vpi, x1, y1, x2, y2, x3, y3, ..)

Internal condition (vector potential constant) within the defined area

Parameter
vpr Real part of vector potential [Vs/m]
vpi Imaginary part of vector potential [Vs/m]
xi, yi Point of the area surounding polygon

Command: def_nccond_vpo(x1, y1, x2, y2)

Definition of the condition of any node chain, vector potential = 0

Parameter
x1,y1 Start-point coordinates [unit]
x2,y2 End-point coordinates [unit]

Command: def_nccond_vpc(x1, y1, x2, y2, vpr, vpi)

Definition of the condition of any node chain, vector potential = constant

Parameter
x1,y1 Start-point coordinates [unit]
x2,y2 End-point coordinates [unit]
vpr Real part of vector potential [Vs/m]
vpi Imaginary part of vector potential [Vs/m]

Command: del_bcond()

Delete all boundary conditions