[Radiance-general] Strange gendaylit behavior

[Rob Guglielmetti]

Getting the error is a good thing, my problem is that depending on how I call gendaylit, I either get or I don't and it prints garbage. Gendaylit is a little fragile when the sun's near the horizon anyway; Axel Jacobs pointed this out in his "learning rtcontrib" tutorial as well. 

Andy McNeil has a good idea that he illustrated in one of his talks at the Radiance Workshop, he looks for gendaylit errors and if thrown, he uses gensky instead. I'm trying to implement something similar here, but as I said the gendaylit STDERR is behaving unreliably, it seems. Maybe it's best to test for zero values in the weather input data and just default to gensky for those timesteps, or something. 

I dunno, I have a headache. Happy weekend y'all.

- Rob

On Oct 7, 2011, at 7:00 PM, Jia Hu wrote:

> Hi Rob:
> 
> I run it in Ubuntu. Please see bellow. It seems no errors.  The error you got says the sky_brightness is out of range, the upper range of skybrightness is 0.6. I did check the code but can not figure out why you have such errors. The skybrightness is calculated by: 
> 
> diffusirradiance * air_mass() / solar_constant_e*get_eccentricity(). 
> 
> ********************
> double get_eccentricity()
> {
> 	double day_angle;
> 	double E0;
> 
> 	day_angle  = 2*M_PI*(daynumber - 1)/365;
> 	E0         = 1.00011+0.034221*cos(day_angle)+0.00128*sin(day_angle)+
> 	    0.000719*cos(2*day_angle)+0.000077*sin(2*day_angle);
> 
> 	return (E0);
> 
> }
> ===============================
> 
> jiahu at jiahu:~$ gendaylit 7 19 19:00:00 -a 39.740000000000002 -o -105.18000000000001 -m -105.0 -L 0.0 1926.55187439894
> # gendaylit 7 19 19:00:00 -a 39.740000000000002 -o -105.18000000000001 -m -105.0 -L 0.0 1926.55187439894
> # Ground ambient level: 2.8
> 
> void brightfunc skyfunc
> 2 skybright perezlum.cal
> 0
> 10 2.091e+00 5.556e-01 0.524236 -0.570392 0.832619 -0.637964 0.014613 -0.907109 0.416674 0.059465 
> 
> ===================================
> # /usr/bin/gendaylit 7 19 19:00:00 -a 39.740000000000002 -o -105.18000000000001 -m -105.0 -L 0.0 1926.55187439894
> # Ground ambient level: 2.8
> 
> void brightfunc skyfunc
> 2 skybright perezlum.cal
> 0
> 10 2.091e+00 5.556e-01 0.524236 -0.570392 0.832619 -0.637964 0.014613 -0.907109 0.416674 0.059465
> 
> =================================
> 
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