47 lines
1.8 KiB
Markdown
47 lines
1.8 KiB
Markdown
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<h1>Configuring the simulation</h1>
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Before you start running your own experiments there are few details to take into
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account at the time of configuring your simulation. In this document we cover
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the most important ones.
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For the full list of settings please see [CARLA Settings](carla_settings.md).
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Fixed time-step
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The time-step is the _simulation-time_ elapsed between two steps of the
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simulation. In video-games, this _simulation-time_ is almost always adjusted to
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real time for better realism. This is achieved having a **variable time-step**
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that adjusts the simulation to keep up with real-time. In simulations however,
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it is better to detach the _simulation-time_ from real-time, and let the
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simulation run as fast as possible using a **fixed time-step**. Doing so, we are
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not only able to simulate longer periods in less time, but also gain
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repeatability by reducing the float-point arithmetic errors that a variable
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time-step introduces.
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CARLA can be run in both modes.
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<h4>Variable time-step</h4>
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The simulation tries to keep up with real-time. To do so, the time-step is
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slightly adjusted each update. Simulations are not repeatable. By default, the
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simulator starts in this mode
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<h4>Fixed time-step</h4>
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The simulation runs as fast as possible, simulating the same time increment on
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each step. To run the simulator this way you need to pass two parameters in the
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command-line, one to enable the fixed time-step mode, and the second to specify
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the FPS of the simulation (i.e. the inverse of the time step). For instance, to
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run the simulation at a fixed time-step of 0.2 seconds we execute
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$ ./CarlaUE4.sh -benchmark -fps=5
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It is important to note that this mode can only be enabled when launching the
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simulator since this is actually a feature of Unreal Engine.
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Synchronous vs Asynchronous mode
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--------------------------------
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> TODO
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