[yt-users] chemical species abundances discrepancy

[poetaste at gmail.com]

Hi Guys,
I did a simple test with enzo and I tried to plot a radial profile of  
the chemical species fractions with YT.

The problem is that if I use the YT function which intrinsically plot  
the fraction for a species, let's say H2I_Fraction (as usual), and  
compare this with a direct evaluation of the mass fraction:

data['H2I_Density']/data['Density']

I obtain some slightly different results, mostly at large radii.

Anyone might explain this discrepancy!? This happens with all the  
species.

Thank you in advance
Stefano