Unitful.md

Unitful

The Julia package Unitful provides units so that calculations can be performed with physical quantities instead of numbers only. The package can be installed with Pkg.add("Unitful"). The Unitiful homepage presents a documentation of the relevant functions in order to work with units.

Working with untis

In electrical engineering I recommend to load the Unitful package as well as the default units Unitful.DefaultSymbols, in addition to EE:

using Unitful,Unitful.DefaultSymbols,EE

Between number and quantity, no blank is allowed.

julia> V1=3.0V
3.0 V
julia> I1=1.0mA
1.0 mA
julia> R1=V1/I1
3.0 V mA^-1

In oder to get a formatted output with six significant digits and a selected unit, function printuln (provied by EE.jl) can be used:

julia> printuln("R1",R1,Ω)
              R1 = 3000 Ω

Brief summary of Unitful function

uconvert

Converts a quantity to a different unit within the same dimension.

julia> uconvert(mV,V1)
3000.0 mV

unit

Determine the used unit

julia> unit(V1)
V
julia> unit(I1)
mA

upreferred

Determine a quantify in coherent (preferred) units, i.e., the SI unit without prefix, except kg.

julia> upreferred(V1)
3.0 kg m^2 A^-1 s^-3
julia> upreferred(I1)
0.001 A

Additionally, this function can be used to determine coherent unit of a non-coherent unit.

julia> upreferred(mA)
A

ustrip

Determine the number of physical quantity. It is important to note, that this does not automatically give the number in coherent SI units.

julia> ustrip(V1)
3.0
julia> ustrip(I1)
1.0

In order to get the number of the coherent SI quantity, use:

julia> ustrip(upreferred(I1))
0.001