== 2013-10-25 ==

To test the behavior of the recent psStats changes on less simple distributions, a series of simulated images were constructed in ppSim.  All images were constructed such that all stars are generated with the same magnitudes and positions across runs.  To explore a range of astronomical situations, simulations were constructed over a grid in the STARS.DENSITY and SKY.MAGS parameters.  The SKY.MAGS value was sampled every two magnitudes between 15 and 25.  The STARS.DENSITY was sampled in log10 space, with samples at log(density) = (-3,-2,-1,0,0.25,0.5,0.75,1.0,1.25,1.5,1.75,2).  Densities higher than this became unreasonably long to run.  The remaining ppSim options used were:
{{{
ppSim -type OBJECT -filter r -skymags $sky -ra 270.70 -dec -23.70 -pa 0.0 -Df PSASTRO:DVO.GETSTAR.MAX.RHO 50000.0 -exptime 10.0 -D PSF.MODEL PS_MODEL_GAUSS -Df STARS.DENSITY $density -Db STARS.REAL F -camera SIMTEST -recipe PPSIM STACKTEST.RUN -D PSASTRO:PSASTRO.CATDIR catdir.ref -Db STARS.FAKE T -Db MATCH.DENSITY F -Db PSF.CONVOLVE T  $outname -seeing 1.0 -seed 12345
}}}

The first table of plots shows the comparison between the current operations tag and the trunk psStats values for the robust and fitted mean and sigma.  For the skymag=25 case, the histograms of a selected set of stellar densities are plotted, along with vertical lines denoting the locations of the means and +/- sigma values.  Note that high density fitted statistics failed in the tag version of psStats for density > 1.0, and as such, no values are plotted.

|| Statistic || Means || Sigma ||
|| tag robust||[[Image(tag_sky25_robust_mean.png,400px)]] || [[Image(tag_sky25_robust_sigma.png,400px)]] ||
|| trunk robust || [[Image(trunk_sky25_robust_mean.png,400px)]] || [[Image(trunk_sky25_robust_sigma.png,400px)]] ||
|| tag fitted|| [[Image(tag_sky25_fitted_mean.png,400px)]] || [[Image(tag_sky25_fitted_sigma.png,400px)]] ||
|| trunk robust || [[Image(trunk_sky25_fitted_mean.png,400px)]] || [[Image(trunk_sky25_fitted_sigma.png,400px)]] ||

The second table shows the measured ratios of the mean and sigma values to those values for the density=-3 case (representing "truth").

|| Statistic || Means || Sigma ||
|| Tag       || [[Image(tag_mean_comparisons.png,400px)]] || [[Image(tag_sigma_comparisons.png,400px)]] ||
|| Trunk     || [[Image(trunk_mean_comparisons.png,400px)]] || [[Image(trunk_sigma_comparisons.png,400px)]] ||