Message: New day, substantially different answers Not Logged In (login)
 Next-in-Thread Next-in-Thread
 Next-in-Forum Next-in-Forum

None New day, substantially different answers 

Forum: Analysis
Date: 18 Dec, 2017
From: Steven Walton <Steven Walton>

I'm not sure which forum is best to put this in, so I'm trying it here.

I have not changed any code, but the answers I'm getting back are substantially different than ones I was running last week. My code is saved through an internal git, so I worked my way back through commits with several known working ones and am still getting the different results.

My code is based on the basic 3 example.

To exemplify the difference, in a run of 1,000,000 particles (which had been enough to converge the solution) would result in 43.2GeV and 42.8GeV on two detectors. Now those same detectors read 46.7GeV and 43.5GeV, respectively. The former had matched experimental results, and the latter are about 8 times larger.

I am trying to figure out what could possibly change the results like this. The solution had been working for 2 weeks before this large change happened. There had been several computer restarts, so I do not think it could be a change in the random number seed.

Side Note: May be related or not, but I was getting an error where using cmath's abs function resulted in a negative number when dividing by eV

eg:

abs((anodeEnergy - cathodeEnergy) / eV)

But now that error doesn't happen and I can't reproduce it, so I'm not sure if it is related.

Inline Depth:
 1 1
 All All
Outline Depth:
 1 1
 2 2
 All All
Add message: (add)

1 None: Re: New day, substantially different answers   (Ivana Hrivnacova - 16 May, 2018)
 Add Message Add Message
to: "New day, substantially different answers"

 Subscribe Subscribe

This site runs SLAC HyperNews version 1.11-slac-98, derived from the original HyperNews


[ Geant 4 Home | Geant 4 HyperNews | Search | Request New Forum | Feedback ]