bessel.lisp error codes and noisy quad_qagi



On Fri, Nov 11, 2011 at 2:00 PM, Edwin Woollett <woollett at charter.net>wrote:

>
>
> Raymond Toy reported that ierr = 2 indicated
> overflow in bessel.lisp.
>
> What do the rest of the ierr values returned
> in bessel.lisp indicate?
>
> In particular, I am interested in 3 and 4.
>

zbesk is in zbesk.f in src/numerical/slatec/fortran.  From the comments
there:

C           IERR   - Error flag
C                    IERR=0  Normal return     - COMPUTATION COMPLETED
C                    IERR=1  Input error       - NO COMPUTATION
C                    IERR=2  Overflow          - NO COMPUTATION
C                            (abs(Z) too small and/or FNU+N-1
C                            too large)
C                    IERR=3  Precision warning - COMPUTATION COMPLETED
C                            (Result has half precision or less
C                            because abs(Z) or FNU+N-1 is large)
C                    IERR=4  Precision error   - NO COMPUTATION
C                            (Result has no precision because
C                            abs(Z) or FNU+N-1 is too large)
C                    IERR=5  Algorithmic error - NO COMPUTATION
C                            (Termination condition not met)
C

Ray