ValidateGeom < LinearCollider

LinearCollider Web>ValidateGeom (2014-12-10, DanProtopopescu) (raw view)
---+ Geometry validation

Once the desired geometry is implemented in DD4hep, one need a way to compare it with the existing descriptions from Mokka or !GeomConverter. This wiki describes several options for doing this. Lots of thanks to Andrei Ghea&#539;&#259; and Nikiforos Nikiforou for demonstrating how various tools work.

%TOC%

---++ Visual validation

First step is of course visual validation.To compare by eye an existing geometry with the newly implemented geometry in DD4hep, one should use the visualisation tools described in the [[VisuDet]] wiki.


---++ Checking overlaps

Let's say we start with the =examples/CLICSiD= geometry and we remove everything except the ECal Barrel and !EndCap components. 

Running =./geoDisplay compact/ECal.xml= as described [[AddDetDD4hep][here]], we load this geometry in memory and display it using the TGeo class from ROOT:

<img src="%PUBURLPATH%/%WEB%/%TOPIC%/ECal1.png" alt="ECal1.png" width="470" height="304" />

To check overlaps or extrusions, from ROOT prompt run
<verbatim>
root [0]  gGeoManager->CheckOverlaps(0.01);
</verbatim>
where the precision is given in =cm=. This will report any overlaps/extrusions:
<verbatim>
...
Info in <TGeoNodeMatrix::CheckOverlaps>: Number of illegal overlaps/extrusions : 31
</verbatim>
To visualise the overlaps/extrusions, navigate in the ROOT =TBrowser= to *world* &rarr; *Illegal overlaps* and you will be able to see something like this:

<img src="%PUBURLPATH%/%WEB%/%TOPIC%/extrusion.png" alt="extrusion.png" width="544" height="522" />

The offending subvolumes are highlighted in red. Some other useful commands:
<verbatim>
gGeoManager->cd(“/path/to/volume/”); // to check only a subvolume
gGeoManager->GetPath();   // to see current path
gGeoManager->getCurrentNode()->CheckOverlaps(0.01);
gGeoManager->PrintOverlaps();
</verbatim>

---++ Shooting particles with Geant4/SLIC

One can shoot particles using SLIC MC, and save output to a slcio file, then use =anajob= or  =dumpevent=  to compare hit positions.

To do this, setup =ilcsoft= to get access to SLIC and the LCIO libraries (for later processing of slcio files). Then create a file, e.g. =particleGun.mac=, containing something like this:
<verbatim>
/run/initialize
/generator/select gps
/gps/pos/type Point
/gps/pos/centre 0. 0. 0.
/gps/ang/type iso
/gps/ang/mintheta 90 deg
/gps/ang/maxtheta 90 deg
/gps/ang/minphi 10 deg
/gps/ang/maxphi 10 deg
/gps/ene/type Mono
/gps/ene/mono 99.8944 GeV
/gps/ene/gradient 0
/gps/ene/intercept 1
/gps/particle mu-
/random/seed 123456789
/run/beamOn 1 
</verbatim>

Run *SLIC*, loading the geometry and running this macro:
<verbatim>
slic -g geometry.lcdd -m particleGun.mac
</verbatim>

This will create a file named =outfile.slcio=. Now run:
<verbatim>
anajob outfile.slcio
</verbatim>
to see hit counts, or 
<verbatim>
dumpevent outfile.slcio 1
</verbatim>
or use =dumpHits.py= ([[%PUBURLPATH%/%WEB%/%TOPIC%/dumpHits.py.txt][attached]], modify at will) to print various hit parameters. For this to run, SLIC must be built with  BUILD_ROOTDICT=ON.


---++ Stress tests

There is a TGeo tool for checking geometries. Although written for testing actual TGeo class implementations, one could use this to compare for example two descriptions produced let's say via different frameworks, and spot if any differences were introduced. A good description of how it actually works can be found in the header of the [[http://root.cern.ch/svn/root/tags/v5-34-07/test/stressGeometry.cxx][C++ source file]]

Go to directory =$ROOTSYS/test= and edit =stressGeometry.cxx= to add a custom entry. In my case a =diff= shows these changes:
<verbatim>
[protopop@ppelx ECal]$ diff $ROOTSYS/test/stressGeometry.cxx.orig $ROOTSYS/test/stressGeometry.cxx
78c78
< const Int_t NG = 33;
---
> const Int_t NG = 34;
82a83
>                         "clicd",
116a118
> 			     1, //clicd - added by protopop@cern.ch
150a153
>                               0.4,  //clicd
184a188
>                          {900,900,1400},    // clicd
255a260,262
>       if(i==4)
> 	TGeoManager::Import(Form("http://www.ppe.gla.ac.uk/~protopop/clic/%s", fname.Data()));
>       else
</verbatim>
where the original geometry file *clicd.root* was created with =gGeoManager->Export("clicd.root");= after importing it from another format, e.g. GDML (and removing for this example everything but the ECal).

We recompile
<verbatim>
source /afs/phas.gla.ac.uk/data/ilc/software/ilcsoft/v01-17/init_ilcsoft.sh
cd $ROOTSYS/test/
make stressGeometry
</verbatim>
and run
<verbatim>
./stressGeometry clicd
</verbatim>
This will generate a file called =clicd_ref_1.root= and put it in =$ROOTSYS/test/files=. This is the reference that will be used for all our subsequent comparisons.

Now let's say we want to compare our newly implemented geometry with the original. We save our [[AddDetDD4hep][new geometry]] with
<verbatim>
gGeoManager->Export("ECal_new.root");
</verbatim>
and we put it in the same location as above (http://www.ppe.gla.ac.uk/~protopop/clic/clicd.root), e.g. =cp ECal_new.root ~/web/clic/clicd.root=

For example, if we have changed =EcalEndcap_zmin= from  =165.70cm= to =164.70cm= between the two models, we get

<img  style="float:right" src="%PUBURLPATH%/%WEB%/%TOPIC%/EcalEndcap_zmin_change.png" alt="EcalEndcap_zmin_change.png" width="200" height="191" />

<verbatim>
[protopop@ppelx test]$ ./stressGeometry clicd
...
Info in <TFile::OpenFromCache>: using local cache copy of http://root.cern.ch/files/clicd_ref_1.root [./files/clicd_ref_1.root]
Reference file http://root.cern.ch/files/clicd_ref_1.root found
 ==>Point 45 differs with diff = 35.4858, x=47.3349, y=4.26597, z=-370.913
    p.nbound=112, p.length=907.019, p.safe=129.087, p.rad=724.119
      nbound=116,   length=907.019,   safe=129.087,   rad=759.605
...
 ==>Point 1057 differs with diff = 63.411, x=-39.6917, y=-27.223, z=166.572
    p.nbound=75, p.length=795.659, p.safe=0.0221592, p.rad=574.564
      nbound=80,   length=795.659,   safe=0.0221592,   rad=637.975
******************************************************************************
*Tree    :TD        : TGeo stress diff                                       *
*Entries :      160 : Total =           10359 bytes  File  Size =       5420 *
*        :          : Tree compression factor =   1.00                       *
******************************************************************************
*Br    0 :p         : x/D:y/D:z/D:theta/D:phi/D:rad[4]/F                     *
*Entries :      160 : Total  Size=       9993 bytes  One basket in memory    *
*Baskets :        0 : Basket Size=      32000 bytes  Compression=   1.00     *
*............................................................................*
*     stress clicd            found    80 bad points ............. failed
******************************************************************
</verbatim>
The statistics can be adjusted by changing =Npoints = 10000;= from its default.

And here's the optimised version of [[%PUBURLPATH%/%WEB%/%TOPIC%/stressGeometry.cxx][stressGeometry.cxx]] which I've been using lately. Easier to use in conjunction with this script: 
[[%PUBURLPATH%/%WEB%/%TOPIC%/compare.sh][compare.sh]].

---++ Troubleshooting

If you don't have that already, then [[CustomRootInstall][install your own version of ROOT]], so that you can customise it. 

You might have to delete ROOT's local cache of the geometry file (=clicd.root= in the above example), or simply store it locally in order to make sure the newest version is loaded for comparison with the reference. Once created, the reference remains in =$ROOTSYS/test/files/= and you will have to delete it to force the creation of a new one.
Attachments
Topic attachments
I	Attachment	History	Action	Size	Date	Who	Comment
png	ECal1.png	r1	manage	17.7 K	2014-06-19 - 14:00	DanProtopopescu	ECal visualised in geoDisplay
sh	compare.sh	r1	manage	0.6 K	2014-12-10 - 11:53	DanProtopopescu	Shell script to use in conjunction with stressGeometry
txt	dumpHits.py.txt	r2 r1	manage	1.1 K	2014-06-24 - 14:27	DanProtopopescu	Script used to extract hit positions from slcio file
png	extrusion.png	r1	manage	32.2 K	2014-06-19 - 14:01	DanProtopopescu	Extrusion detected by CheckOverlaps()
cxx	stressGeometry.cxx	r1	manage	23.4 K	2014-12-10 - 11:44	DanProtopopescu	Modified stressGeompetry.cxx source file
Topic revision: r12 - 2014-12-10 - DanProtopopescu
LinearCollider