Browse Prior Art Database

Simulation Recording and Playback

IP.com Disclosure Number: IPCOM000124822D
Original Publication Date: 2005-May-09
Included in the Prior Art Database: 2005-May-09
Document File: 1 page(s) / 20K

Publishing Venue

IBM

Abstract

The problem being solved is how to capture a simulation run in such a way that it can be played back at a later time but still allow the playback to be interrupted and then resumed independently of the recording.

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Simulation Recording and Playback

This publication discribes a solution to the simulation recordinal and playback problem continuously logging the state of the simulation into a log file. Later, this log file can be streamed into a simulation to reproduce that exact simulation. This playback can be interrupted to inspect the simulation state (attributes, activities) or to modify the simulation attributes. In the former, the simulation is resumed from the streaming input. Modification of the simulation attributes results in disconnecting the simulation from the streaming input and reverting to a non-recorded simulation.

This solution is based on two simple concepts:
1. Recording in a log every point where data is being generated.
2. Playback from a log for every point where data was generated.

To address point #1, all references to simulation parameters must be identified and wrapped with a record/playback mechanism. Values which are invariant (e.g. a fixed cost) or are calculated (e.g. the statistics) need not be recorded or played back. The values which must be recorded and played back include:
1. Values from random distributions
2. Values provided by external sources (expressions and processor objects)
3. Volitile values (e.g. the current time)

It might be possible to do away with the first two cases if they are determined to be invariant. For example, if the predefined distributions are being used and a random seed is provided to the simulation engine then the resu...