Re: TMatrix compatibility between v3.10/02 and v4.03/02

Hi Chris and Rene,

Chris is right . Indeed, we should transpose matrices in the streamer coming from root versions < 4 . Currently, I have not good access to the internet ,
but I will try to upload a small patch tomorrow .

Eddy

• Chris Crawford <chris2_at_lns.mit.edu> wrote:
  > Hi Rene,
  > Here is an example:
  > --thanks, Chris
  >
  > // root-v3.10/02
  > {
  > TFile f("a.root","recreate");
  > TMatrix m(2,3);
  > m(0,0)=1; m(0,1)=3; m(0,2)=5;
  > m(1,0)=2; m(1,1)=4; m(1,2)=6;
  > m.Print();
  > m.Write("m");
  > m.GetElements();
  > f.Close();
  > }
  >
  > Matrix 2x3 is as follows
  >
  > | 0 | 1 | 2 |
  > ------------------------------------------------------------------
  > 0 | 1 3 5
  > 1 | 2 4 6
  >
  > elements: [ 1 2 3 4 5 6 ]
  >
  > //root-v4.01/02 or v4.03/02
  > {
  > TFile f("a.root");
  > m->Print();
  > m->GetMatrixArray();
  > }
  >
  > 2x3 matrix is as follows
  >
  > | 0 | 1 | 2 |
  > ------------------------------------------------------------------
  > 0 | 1 2 3
  > 1 | 4 5 6
  >
  > elements: [ 1 2 3 4 5 6 ]
  >
  > Rene Brun wrote:
  >
  > >Hi Chris,
  > >
  > >ROOT version 4 is already doing this. You should be able to read
  > >old style matrices with the new version.
  > >Could you send a very short file with an example that does not work?
  > >
  > >Rene Brun
  > >
  > >On
  > >Fri, 25
  > >Mar 2005, Chris Crawford wrote:
  > >
  > >
  > >
  > >>Hello,
  > >> When I try and read TMatrices from v3 root files in root-v4, it
  > >>switches between row-major and column major, jumbling up the
  > entries.
  > >>Is there some way that the class Schema can fix this? I notices
  > the
  > >>class version jumped from 2 to 3.
  > >>--thanks, Chris
  > >>
  > >>
  > >>
  >
  >