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NextTimeStep
The first input value to be found before each (output) timestep is stored in the output timeserie.
Block
The first input value to be found after each (output) timestep is stored in the output timeserie, and repeated until a new value is found.
Linear
The value of each output timestep is calculated, by interpolating the input values just before and after the output timestep. Essentially, the value is found at the point where the line connecting these values, crosses the timestep.
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