Activity output types

Activity outputs can be of five different types:

Constant

Activity outputs of this type are always have a constant value for all time points.

For instance, the following activity output named test_output always have the value f = 2:

activity = sund.Activity(time_unit = "s")
activity.add_output("constant", "test_output", f = 2)

Piecewise constant

Activity outputs of this type are have different constant values between specified time points. All activity outputs of this type always have a default value outside of specified time points.

For instance, the following activity output named test_output has the default value f = 2 prior to the specified time points and the value f = 1 from time point t = 1 and the value f = 3 from time point t = 2 and the value f = 2.5 from the time point t = 3. In other words, at t = [1, 2, 3], f assumes the values f = [1, 3, 2.5], with a default value (before the first time point) at 2:

activity = sund.Activity(time_unit = "s")
activity.add_output("piecewise_constant", "test_output", t = [1, 2, 3], f = [2, 1, 3, 2.5])

Piecewise linear

Activity outputs of this type have values based on linear equations between specified values at specified time points.

For instance, the following activity output named test_output has a linearly decreasing value from f = 2 to f = 1 between time points t = 0 and t = 1, a linearly increasing value from f = 1 to f = 3 between time points t = 1 and t = 2 and a linearly decreasing value from f = 3 to f = 2.5 between time points t = 2 and t = 3:

activity = sund.Activity(time_unit = "s")
activity.add_output("piecewise_linear", "test_output", t = [0, 1, 2, 3], f = [2, 1, 3, 2.5])

Cubic spline

Activity output of this type have values based on natural spline interpolation, conforming to specific values at specific time points.

For instance, the following activity output named test_output has its value as a cubic function conforming to the values f = 2 at t = 0, f = 1 at t = 1, f = 3 at t = 2 and f = 2.5 at t = 3:

activity = sund.Activity(time_unit = "s")
activity.add_output("cubic_spline", "test_output", t = [0, 1, 2, 3], f = [2, 1, 3, 2.5])

Cubic spline with slope

This output type is not fully supported and will be removed in a future version.