<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">Hi Britton,</div><div class="gmail_quote"><br></div><div class="gmail_quote">Thanks for the help.  I'm getting an error trying to use halo.data_container.</div><div class="gmail_quote"><div class="gmail_quote">     14 hc.add_callback("sphere",factor=1.0)</div><div class="gmail_quote">     15 def _gas_mass(halo):</div><div class="gmail_quote">---> 16     return halo.data_container.quantities.total_quantity("cell_mass")</div><div class="gmail_quote">     17 </div><div class="gmail_quote">     18 add_quantity("gas_mass",_gas_mass)</div><div class="gmail_quote"><br></div><div class="gmail_quote">AttributeError: 'Halo' object has no attribute 'data_container'</div><div class="gmail_quote"><br></div><div class="gmail_quote">I've made my code very simple and am using the example data to debug this. I'm just trying to get the total gas mass for now</div><div class="gmail_quote"><br></div><div class="gmail_quote"><div class="gmail_quote">data_ds = yt.load('Enzo_64/RD0006/RedshiftOutput0006')</div><div class="gmail_quote">halos_ds = yt.load('rockstar_halos/halos_0.0.bin')</div><div class="gmail_quote"><br></div><div class="gmail_quote">def _gas_mass(halo):</div><div class="gmail_quote">    return halo.data_container.quantities.total_quantity("cell_mass")</div><div class="gmail_quote"><br></div><div class="gmail_quote">add_quantity("gas_mass",_gas_mass)</div><div class="gmail_quote"><br></div><div class="gmail_quote"># Instantiate a catalog using those two paramter files</div><div class="gmail_quote">hc = HaloCatalog(data_ds=data_ds, halos_ds=halos_ds)</div><div class="gmail_quote"><br></div><div class="gmail_quote">hc.add_callback("sphere",factor=1.0)</div><div class="gmail_quote">hc.add_quantity("gas_mass")</div><div class="gmail_quote">hc.create()</div><div class="gmail_quote"><br></div><div class="gmail_quote">Any help would be appreciated.</div><div class="gmail_quote"><br></div><div class="gmail_quote">Thanks,</div><div class="gmail_quote"><br></div><div class="gmail_quote">Ari</div></div></div></div></div>