fix bug :: in DGESDD, workspace query gives a value smaller than the minimal value given in the header to run the routine

    o reported by  Guy Bencteux on Sat Dec 06 2008
    o see forum topic 846 : https://icl.cs.utk.edu/lapack-forum/viewtopic.php?f=2&t=846

remove a min(M,N) in the minimal workspace formula when JOBZ='O' and  JOBZ = 'S' or 'A'.

Note Julie on minimal value:
Case: M > N

IF( M > N*5.0D0  ) THEN
PATH 1 -> FOR JOBZ=N : MINWORK = 7*N + N
PATH 2 -> FOR JOBZ=O: MINWORK = 5*N*N + 7*N
PATH 3 -> FOR JOBZ=S: MINWORK = 4*N*N + 7*N	
PATH 4 -> FOR JOBZ=A:  MINWORK = 4*N*N + 7*N


IF M>N (but not too large)
PATH 5 -> FOR JOBZ=N : MINWORK = MAX(7*N,M) + 3*N
PATH 6 -> FOR JOBZ=O: MINWORK = 3*N + MAX (M,4*N*N + 4*N)
PATH 7 -> FOR JOBZ=S : MINWORK = 3*N + MAX (M,3*N*N + 4*N)
PATH 8 -> FOR JOBZ=A :  MINWORK = 3*N + MAX (M,3*N*N + 4*N)
			
GENERAL FORMULA FROM THE TWO CASES WHEN M>N
FOR N LWORK >= 3*N + max (M,7*N)	
FOR O LWORK >= 3*N + max (M,5*N*N + 4*N) [instead of 3*N*N + max (M,5*N*N + 4*N) ]
FOR S ET A LWORK >= 3*N + max(M,4*N*N + 4*N) [instead of 3*N*N + max(M,4*N*N + 4*N) ]

0 files changed, 0 insertions, 0 deletions