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Testing seed change in GlastSvc
GlastRandomSvc.autoSeed = false; // per run random seed, new default
vs
GlastRandomSvc.autoSeed = true; // per event random seed, old default
The change to seed determination in GlastSvc is the cause of the differences in several system test distributions. Most notably CalColumn, hit distributions in the Tracker by layer or depth, and integrating and position hits. In other words, the events are different just because of the MC seeding.
A limited test of reversting of this to the previous behavior removed all differences. See System Tests v15r47p12gr06C for the comparison of the AllGamma and BackGndMixDC2 tests using the previous seed method (specified int he JO by "GlastRandomSvc.autoSeed = true;").
Here is one comparison example for both GR v1547p12gr06 with the new seed behavior and for the former behavior (gr06C).
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