Hi LAPACK developers,
I encountered a convergence problem of DLAHQR in V.3.5.0. However V.2.0 converged for the same problem.
I found a difference between two versions as shown below.
NH = IHI - ILO + 1
ITN = 30*NH
DO 130 ITS = 0, ITN
PARAMETER ( ITMAX = 30 )
DO 140 ITS = 0, ITMAX
ITN and ITMAX are the maximum number of QR iterations.
Modified V.3.5.0, where ITMAX is changed to ITMAX*NH, converged for the same matrix.
Is this a bug or intentionally changed?