The clock holds the current simulation time, iteration number, and time step stage. The time step stage is relevant only for the multi-stage time-stepper RungeKutta3TimeStepper.

By default, Clocks are initialized at iteration 0, and stage 1,

julia> clock = Clock(time=0.0)
Clock{Float64, Float64}: time = 0 seconds, last_Δt = Inf days, iteration = 0, stage = 1

but can be modified to start the model clock at some other time. For example, passing

julia> clock = Clock(time=3600.0)
Clock{Float64, Float64}: time = 1 hour, last_Δt = Inf days, iteration = 0, stage = 1

to the constructor for NonhydrostaticModel causes the simulation time to start at $t = 3600$ seconds.

The type of the keyword argument time should be a float or date type. To use the date type TimeDate from the TimesDates.jl package, for example, pass

julia> using TimesDates

julia> clock = Clock(time=TimeDate(2020))
Clock{TimesDates.TimeDate, Float64}: time = 2020-01-01T00:00:00, last_Δt = Inf days, iteration = 0, stage = 1

to NonhydrostaticModel. TimesDates.TimeDate supports nanosecond resolution and is thus recommended over Base.Dates.DateTime, which is also supported but has only millisecond resolution.