# TimeStepper System

The method used to calculate the size of the time steps is controlled by the `TimeStepper`

block. There are a number of types of TimeStepper available, each of which controls the time stepping in different ways, including using fixed time stepping, time stepping based on a function, or adaptive time stepping.

## Available Objects

- Moose App
- AB2PredictorCorrector
- CSVTimeSequenceStepperSolves the Transient problem at a sequence of given time points read in a file.
- ConstantDTTimestepper that takes a constant time step size
- DT2
- ExodusTimeSequenceStepperSolves the Transient problem at a sequence of time points taken from a specified exodus file.
- FunctionDTTimestepper whose steps vary over time according to a user-defined function
- IterationAdaptiveDTAdjust the timestep based on the number of iterations
- LogConstantDTTimeStepper which imposes a time step constant in the logarithmic space
- PostprocessorDT
- SolutionTimeAdaptiveDT
- TimeSequenceStepperSolves the Transient problem at a sequence of given time points.
- External Petsc Solver App
- ExternalPetscTimeStepperTimestepper that queries the step size of the external petsc solver, and use that as the time step size.

## Available Actions

- Moose App
- SetupTimeStepperAction