"M. Sievers" wrote: > > On Wed, 3 Nov 1999, Nick van Eijndhoven wrote: > > > Hi Victor, > > Maybe I am missing a point here, but the dotproduct you mention > > below has to my opinion no physical meaning and as such I would > > say should not be supported or at least the user should receive a > > warning message that he/she is doing nonsense. > > However, as I said I may be missing a point here and then I am > > saying nonsense. > > I'd say a dot product with a three-Vector makes sense much in the same way > as an angle to a three-vector does! You could make a four-vector for > example by taking tracking information for the momentum and calorimeter > information for the energy (should be possible...). And you should still > be able to compare it to other tracks! > > Bye, > Mike Completely agree. A simple example. You have some direction (3 vector D) and momentum of a track 4 vector P. Scalar production of them provide you cosine of angle between them. Then this angle is used to estimate effectivity etc. Victor > > -------------------------------------------------------------------------- > Michael Sievers > Michael.Sievers@desy.de > -------------------------------------------------------------------------- > esa$ gcc -Wall -o ariane5 ariane4.c > ariane4.c: 666: warning: long float implicitly truncated to unsigned type > esa$ ariane5 -- Victor M. Perevoztchikov perev@bnl.gov perev@vxcern.cern.ch Brookhaven National Laboratory MS 510A PO Box 5000 Upton NY 11973-5000 tel office : 631-344-7894; fax 631-344-4206; home 631-345-2690
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