Incorrect initialization of TMatrixTSparse

[Axel-Naumann]

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Description

See https://root-forum.cern.ch/t/shift-of-row-index-in-tmatrixtsparse/56525

According to Eddy it's a bug in the initialization of a sparse matrix with a row index not starting at 0.

Reproducer

void testSparse(Int_t msize=5)
{
  TMatrixDSparse m1(1,4,0,msize-1);
  {
    Int_t nr = 4*msize;
    Int_t    *irow = new Int_t[nr];
    Int_t    *icol = new Int_t[nr];
    Double_t *val  = new Double_t[nr];

    Int_t n = 0;
    for (UInt_t i = m1.GetRowLwb(); i <= m1.GetRowUpb(); i++) {
      for (UInt_t j = m1.GetColLwb(); j <= m1.GetColUpb(); j++) {
        irow[n] = i;
        icol[n] = j;
        val[n] = TMath::Pi()*i+TMath::E()*j;
        n++;
      }
    }
    m1.SetMatrixArray(nr,irow,icol,val);
    delete [] irow;
    delete [] icol;
    delete [] val;
  }

  m1.Print();

  TMatrixD m2(1,4,0,msize-1);
  for (UInt_t i = m2.GetRowLwb(); i <= m2.GetRowUpb(); i++)
    for (UInt_t j = m2.GetColLwb(); j <= m2.GetColUpb(); j++)
      m2(i,j) = TMath::Pi()*i+TMath::E()*j;
  m2.Print();

  std::cout << "matrices identical " << ((m1 == m2) ? "OK" : "FAILED") << std::endl;
}

ROOT version

master

Installation method

any

Operating system

any

Additional context

No response