hello:
i agree with doug and michael. for those of you who weren't at the
analysis meeting yesterday, it was pointed out that all results that the
non-BLAST world will see will be shown with the [0, 360] convention.
additionally, all results gotten from the non-BLAST world (in particular,
results received from arenhovel) will be in the [0, 360] convention.
so, to summarize:
pro's of using [-90, 270] convention:
1) one less constraint has to be typed in in order to make plots
"pretty"
2) one less line of code has to be typed in in order to perform
azimuthal averages properly
con's of using [-90, 270] convention:
1) despite the intuitive feel that all existing code should NOT need
to be altered for this new convention, all existing code WILL still
have to be checked; in particular, i can say for SURE that some of
the monte Carlo code will HAVE to be changed, despite an intuitive
feel that it shouldn't
2) this convention does not agree with what the non-BLAST world
understands readily, and results shown to and received from the
non-BLAST world will have to be altered
3) this convention is yet (another) esoteric concept that we would all
have to carry around, as it goes against the spherical angle ranges
that we have all known since 10th grade
but i may be wrong. however, i am not wrong when i say that whatever
angle range convention is adopted, IT MUST BE ADOPTED EVERYWHERE
THROUGHOUT THE RECONSTRUCTION, THE MONTE CARLO, AND blast.geom. yup,
gotta put my foot down on that one...
aaron
On Thu, 3 Apr 2003, Douglas Hasell wrote:
> Hi,
>
> I agree with Michael. Lets stick to a conventional spherical
> system. If we really wanted to solve this and stay with the correct and
> normal definitions for spherical coordinates then we should redefine the
> coordinate systems such that Z is along the beamline, X is vertical, and Y
> points to the right sector but this would be such a major change that I
> think it is too late to do it.
>
> I would not change anything but request that everyone review their
> code and make sure they do not make some silly mistake because they assume
> the azimuthal angle is continuous. They must also specify in the argument
> or result description which range they use or produce. For new code I
> would suggest that we use [0,2pi) and you change it internally if you need
> it continuous over phi=0 and change it back for the final result.
>
> Cheers,
> Douglas
>
> 26-415 M.I.T. Tel: +1 617 258 7199
> 77 Massachusetts Avenue Fax: +1 617 258 5440
> Cambridge, MA 02139, USA E-mail: hasell@mit.edu
>
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