Example: Geant4/examples/extended/persistency/gdml/G01/ 
All comments refer to:
geant 4 release: patch01 for Geant4 9.5 
platform: SLF 6 and UBUNTU

Reviewer: Hans Wenzel


1) Example compiles, runs 
   Yes and a CMakeLists.txt file is provided. Since the new build system is 
   cmake this should be reflected in the readme file for an out of source build:

   building the example:
   mkdir G01-build
   cd G01-build/

   cmake -DGeant4_DIR=/xxx/geant4.9.5.p01-install/lib/Geant4-9.5.1/ \
          /xxx/geant4.9.5.p01/examples/extended/persistency/gdml/G01

   make  load_gdml

remark: since there is only one target for creating an executable (load_gdml) a
simple  make should be sufficient.

In the file
opticalsurfaces.gdml

I find the line:
<matrix name="RINDEX" coldim="2" values="1.65 1.58" />

which means that no unit for the energy of the photon is provided and so
geant 4 will use the default unit of MeV which doesn't make sense for
optical photons
using:

<matrix name="RINDEX" coldim="2" values="1.56258*eV 1.74822
                           1.59515*eV 1.74941 />


That makes it clear and ensures that not MeV are used. I think that way things
 are much clearer. (It probably always better to specify the units)


2) External software documentation (if present)
   fine. The README file lists all the prerequisits. Since Geant 4 switched 
   to cmake as a build system may be one should menion that to build geant 4
   one should use the flag: 
   -DGEANT4_USE_GDML=ON
   

3) Classification of classes
   List classes specific to demonstrated features:
   
   ...   
   
   List of classes which can be replaced with common ones:
   
   ...
   
4) Messenger classes
   n/a no messenger classes provided 

   List commands defined in this example: 
   ...  
   
   List commands which do not work as expected:
   a) not at all
   ...
   
   b) in some G4 phase(s)
   ...
   
5) Code review:
   Report on obsolete code (if present):
   ...
   
   Report on inefficient code (if present):
   ...
   
   Your recommendations to example owner:
   
   
6) Documentation review:
   Your recommendations to example owner:
   As mentioned above the documentation should reflect the use of cmake 
   to build the example. 
   
7) Comment on the adequacy in its physics domain
   (skip this item if you are not an expert in physics demonstrated 
   in the example):
   ...    
   
8) "Users questions to be addressed in examples"   
   List questions which can be naturally addressed in this example:
   Very nice example how to construct detectors using gdml as detector 
   description. Avoidng to have to recompile when the detector geometry 
   changes.