VectorAssign
The VectorAssign function requires 2 parameters (for 2D vectors) or 3 parameters (for 3D vectors). The parameters are assigned to be the components of the vector. This function must be placed after the $Vector (or $Vector2D) directive that identifies a vector variable. EES variables and algebraic expressions may be provided for the components as shown in the following examples.
$Vector A B C
A=VectorAssign(1 [m], 2 [m], 3 [m])
x=3 [ft]; y=4 [ft]; z=5 [ft]
B=VectorAssign(x, y, z)
C=VectorAssign(3*x/4+2 [ft], y, z) [ft]
Units may be defined with the VectorAssign function in two ways. The units may be provided with the x-component, provided that it is a numerical value, as shown above for vector A.
Note that all components in the vector have the same units, so it is only necessary to provide the units for the x-component. In the example above, the units of EES variables A_x, A_y, and A_z will all be set to [m].
Alternatively, units may be specified by following the VectorAssign function with the units, as shown above for vector C. In this case, the units of C_x, C_y and C_z will be set to [ft].
The VectorAssign function may be followed by multiplication/division with a scalar or addition/subtraction of a vector.
$Vector D E
D=VectorAssign(1,1,1)*(3*x) {note that D_x, D_y, and D_z will have the same units as assigned to x}
E=(x+y-z)*VectorAssign(1,1,1)+D
See also: VectorAssignPolar