Re: GEANT-3 grkuta

Hi Andre,
> - Speed of light is 299,792,510 instead of 299,792,458 (PDG value)
you are right, but:
- we never know mag field with accuracy better 1e-6 - grkuta is estimation, neglecting energy loss, multiple scatterring, etc...
So it is no important.

> - In line 110 comparison "IF (EST.GT.H)" assumes that H is positive,
H is always positive. It is a step in direction of particle momentum.

> while if I'm not mistaken it doesn't have to be (and elsewhere
> comparison is always to abs(h))

You right, abs(H) is redundant.

Victor

Victor M. Perevoztchikov perev_at_bnl.gov Brookhaven National Laboratory MS 510A PO Box 5000 Upton NY 11973-5000 tel office : 631-344-7894; fax 631-344-4206;

• Original Message ----- From: "Andre Lebedev" <lebedev_at_fas.harvard.edu> To: <vmc_at_pcroot.cern.ch> Sent: Monday, November 27, 2006 7:09 PM Subject: [VMC] GEANT-3 grkuta

> Hello.
>
> I've noticed 2 minor issues with GEANT3 Runge-Kutta stepper
> - Speed of light is 299,792,510 instead of 299,792,458 (PDG value)
> - In line 110 comparison "IF (EST.GT.H)" assumes that H is positive,
> while if I'm not mistaken it doesn't have to be (and elsewhere
> comparison is always to abs(h))
>
> Neither is a show stopper, but given the fact that G3 is still sort of
> supported in the realm of virtual MC, you may be in a good position to
> address these bugs.
>
> Best regards,
> Andre.
>
Received on Tue Nov 28 2006 - 06:20:41 MET