Re: python ROOT access

Thank you,

going around via defining

xyz=TGeoTranslation()
rot=TGeoRotation()

modifying those and creating
combi=TGeoCombiTrans()
combi.SetTranslation(xyz)
combi.SetRotation(rot) works as advertised :)

Regards
Michal

2008/3/2, Stanley Seibert <volsung_at_physics.utexas.edu>:
> I see the same result with 5.18 on Mac OS X 10.5.2.
>
> The problem is that PyROOT is letting you violate the method signature
> of GetRotationMatrix():
>
> const Double_t *TGeoCombiTrans::GetRotationMatrix() const;
>
> You should not assign values using the Double_t pointer returned by
> the method, as it is declared const. Assignment worked anyway for
> TGeoRotation since the method always returns a pointer to an internal
> buffer in the object. However, TGeoCombiTrans does this:
>
> const Double_t *TGeoCombiTrans::GetRotationMatrix() const
> {
> // get the rotation array
> if (!fRotation) return kIdentityMatrix;
> return fRotation->GetRotationMatrix();
> }
>
> When it takes the first branch, it returns a pre-defined constant
> matrix, which for some reason triggers a segfault when you try to
> modify it.
>
> See the TGeoCombiTrans constructor for the correct way to instantiate
> it with a given offset and rotation.
>
>
> On Mar 2, 2008, at 2:22 PM, Michal Dwuznik wrote:
>
> > Hi ROOTers,
> > could someone with pyROOT configured properly check the following in
> > python:
> >
> > (ROOT 5.19/01)
> >
> > $ python
> > Python 2.5.2 (r252:60911, Feb 27 2008, 18:32:21)
> > [GCC 4.2.3 (Ubuntu 4.2.3-2ubuntu1)] on linux2
> > Type "help", "copyright", "credits" or "license" for more information.
> >>>> import ROOT
> >>>> combi = ROOT.TGeoCombiTrans()
> >>>> matrix = combi.GetRotationMatrix()
> >>>> print matrix[0]
> > 1.0
> >>>> matrix[0]=0.99
> >
> > *** Break *** segmentation violation
> > (no debugging symbols found)
> > Using host libthread_db library "/lib/tls/i686/cmov/libthread_db.so.
> > 1".
> > Attaching to program: /proc/8053/exe, process 8053
> > [Thread debugging using libthread_db enabled]
> > [New Thread 0xb7d428c0 (LWP 8053)]
> > [New Thread 0xb521db90 (LWP 8069)]
> > (no debugging symbols found)...done.
> >
> > 0xb7eef410 in __kernel_vsyscall ()
> > error detected on stdin
> > The program is running. Quit anyway (and detach it)? (y or n)
> > [answered Y; input not from terminal]
> > Detaching from program: /proc/8053/exe, process 8053
> >
> >>>> combi = ROOT.TGeoRotation()
> >>>> matrix = combi.GetRotationMatrix()
> >>>> matrix[0]
> > 1.0
> >>>> matrix[0]=0.99
> >>>> print matrix[0]
> > 0.99
> >
> > In the same time doing quite the same with TGeoRotation instead
> > works OK.
> > What's my error then ? Or what's the proper way of feeding a
> > TGeoCombiTrans
> > from python with [x,y,z] as translation and [1,0,0,0,1,0,0,0,1] as
> > rotation "matrix" ?
> >
> > Regards
> > Michal
>
>
Received on Sun Mar 02 2008 - 22:01:33 CET