Re: [RFC] Astro:: modules
Anyway, here's what I got so far with the Astro:: stuff: Astro::Sun- stuff related to solar position Astro::Moon - stuff related to lunar position Astro::Common - common calculation utilities How common is Common? Remember there is stuff like Astro::FITS::CFITSIO (also a good example of why C interfaces suck in perl) under that namespace. Astro::Earth::Location - simple structure to store latitude/longitude, etc. Do you know how accurate the algorithm is? Our local guru has a 308 term polynomial. :) Astro::BigFloat - Wrapper to Math::BigFloat to allow toggling on/off the use of Math::BigFloat Again, I'm concerned about namespace pollution. I by no means declare that these are good names: I used them just so I could roughly divide things up. Please suggest any ideas you might have. Here are some points that I'm kind of pondering about: - naming. - better organization If all the algorithms are out of the CC book would about something like Astro::Calendrical::* ? - usage? is a plain procedural interface ok? My personal preference is class methods over exporting stuff. use Astro::Sun qw(solar_longitude); my $degrees = solar_longitude($dt); my $degrees = Astro::Sun-solar_longitude( $dt ); I think it makes the code more readable but obviously opinions are varied on this. - I think Astro::Common can be separated out into smaller packages. - when structure is settled, optimize a bit. Once I get the idea of how to organize these modules, I will polish them up, and bring them up again... -J --
Re: [RFC] Astro:: modules
How common is Common? Remember there is stuff like Astro::FITS::CFITSIO (also a good example of why C interfaces suck in perl) under that namespace. CC uses these functions throughout both solar and lunar calculations: julian_centuries nutation obliquity aberration The rest of the stuff involves converting datetime based on location, ephemeris correction, etc. I'm not sure where they would go: # things I think DateTime already handles (I just used CC's # algorithms straight from th book for now): standard_from_universal() universal_from_standard() standard_from_local() local_from_standard() universal_from_local() local_from_universal() # requires ephemeris correction universal_from_dynamical() dynamical_from_universal() # miscellaneous rata_die() - just return DT at 1/1/1 binary_search() search_next() local_from_apparent() equation_of_time() ephemeris_correction() # miscellaneous constants RD_MOMENT_1900_JAN_1 RD_MOMENT_1810_JAN_1 RD_MOMENT_J2000 MEAN_TROPICAL_YEAR MEAN_SYNODIC_MONTH I've tentatively separated out the mathematical stuff out to Astro::CalcUtils (eek, there's *got* to be a better naming). This involves things like polynomial(), angle(), sin_deg()/cos_deg() (trignometric calculations based on degrees). I've also removed Astro::BigFloat in favor of functions in above mentioned Astro::CalcUtils, currently (tentatively) called: bigfloat() bf_downgrade() to handle creation of Math::BigFloat objects (which can be toggled on/off to just return the original value) and downgrade to simple scalars. Astro::Earth::Location - simple structure to store latitude/longitude, etc. Do you know how accurate the algorithm is? Our local guru has a 308 term polynomial. :) Hmm? this was just to store position. No accuracy involved. I can't much speak for the accuracy of CC's algorithms, but seeing the error margin I would use it for datetime calculation, but not for rocket science. --d
Re: Re: FW: DateTime questions...
Matt Wright [EMAIL PROTECTED] wrote: Yes, I noticed this too, but there seemed to be quite a few problems besides just the compiler issue. The Makefile came out very screwy as well, with a lot of missing single quotes, variables without any = signs after them, etc. I had this problem with RH9 also ... seems that perl's Unicode and RH9's Unicode support got all tangled up. I fixed it by changing LANG=en_US in my bashrc to just 'LANG='. I read that somewhere ... anyway it works! I think perl downgraded it's unicode for 5.8.1 because of this. I can't remember it's a while since I researched it. You might want to search perl port. Cheers! Rick
