This package provides a framework for writing, using, and interpreting the output of modular tools for propagating systematic uncertainties within an experimental simulation tool chain.
Experimental physics is lousy with models. The 'event' signatures recorded in detectors are very often ambiguous and thus extensive simulation is needed to interpret what is observed. If these simulations are incorrect (they are), then our interpretation of the underlying physics will be similarly incorrect. To account for this, we make plausible variations of many components of the simulation and hope (assume) that somewhere within the high dimensional space of variations, is a model that describes nature well enough for our purposes. Because of the computing time involved with running a full simulation, it is often attractive to be able to make such variations to a set of simulated observations at 'analysis-', or interpretation-, time. Sometimes these variations can be exactly parameterized and thus the varied, simulated observations are statistically equivalent to having re-run the entire simulation. Sometimes they are approximate.
This package aims to provide a framework for developing and using tools that provide these variations. The framework itself aims to contain no assumptions on the experiment or physics analysis being performed, these are left up to specific implementations that reside in dependent packages.
For a short primer on the main moving parts within systematicstools, see Moving parts.
For a description of the two levels of configuration file, with examples, see Tool Configuration and Parameter Headers.
For tips on how to begin writing a new systematic provider, and a short description of the ISystProviderTool abstract base class, see Writing A Provider.
For an example, and recommended documentation structure, of an ISystProviderTool implementation, see ExampleSystProvider.