Changes between Version 37 and Version 38 of HowToAddSample

Timestamp:

Jan 6, 2017, 1:56:23 PM (8 years ago)

Author:

Clarence Wret

Comment:

--

HowToAddSample

@@ -120 +120 @@
 The `FitEvent` class is an object which contains information about one single event: all the particles, their kinematics and their status after the interaction, the interaction channel which produced the final state, possible secondary interactions, the interaction target, and so on.  The `FitEvent` class is implemented in `src/FitBase/FitEvent.cxx` and essentially the generator-independent common event format which NUISANCE uses for the generator events.
 
-[=!point_signal]
+[=#point_signal]
 We see that the `src/T2K` directory contains `T2K_SignalDef.cxx`. This extends the `SignalDef` namespace which holds many of the signal definitions for the classes. If you're implementing multiple distributions for the same measurement (e.g. dSig/dp,,mu,, and dSig/dcosmu) we recommend adding the signal definition to the namespace rather than directly in the `isSignal(FitEvent *event)` function in the class implementation. We'll talk about implementing a signal definition [#point_signaldef later].
 
+
+'''What to do:'''
 Our header file now looks like:
 
@@ -178 +180 @@
  * `TMatrixDSym *fFullCovar`: The covariance matrix
  * `TMatrixDSym *covar`: The inverted covariance matrix (bad naming, sorry!)
- * `double fScaleFactor`: The scaling factor we need to go from a event rate 
+ * `double fScaleFactor`: The scaling factor we need to go from a event rate to a cross-section (N,,evt,,(p,,mu,,) -> dSig(p,,mu,,))
 
 
@@ -188 +190 @@
  * `Measurement1D::SetupDefaultHist`: sets all the generator histograms and their auxillary histograms (e.g. mode-by-mode generator histograms)
 
-or similar functions (e.g. `Measurement1D::SetDataFromFile` instead of `Measurement1D::SetDataValues`). 
-
-
+or similar functions, e.g. calling `Measurement1D::SetDataFromFile` instead of `Measurement1D::SetDataValues`. '''Feel free to add reasonable setter functions to the base classes if you can't find a suitable one!'''
+
+Current NUISANCE (v1r0) behaviour requires `fName`, `fPlotTitls`, `EnuMin`, `EnuMax` and `fScaleFactor` to be set by user in the implementation file. These are the only variables that need to be supplied by the user in the constructor, granted above helper functions are used.
+
+'''For non-expert use''', it's sufficient to just copy the `fScaleFactor` variable as `(fEventHist->Integral("width")*1E-38)/double(fNEvents)/TotalIntegratedFlux("width");`. This number is applied to the event rate histogram to take us to a cross-section histogram in `Measurement1D::ScaleEvents`.
+
+{{{
+#!div class=important
+If the cross-section is not in cm^2^/nucleon but instead cm^2^/CH (or any other molecule) you will have to scale the `fScaleFactor` by the number of available target nucleons. For CCQE, nu,,mu,, interactions only occur off neutrons, which we have 6 of in CH. But the total number of nucleons in CH is 13. So if an experiment reports cross-section in cm^2^/CH we need to do `fScaleFactor*=13./6.`.
+}}}
+
+It's possible that these will be automated in the future, so please look at [[https://nuisance.hepforge.org/trac/browser/src recently implemented samples]] for up-to-date references.
 
 {{{