Fields of loadTree()

Lara Stockman
  • 1 May '18

hi everyone, I'm trying to decode the mode of operation of loadTree() function. I don't understand why the field "SubhaloID" and the other SubLink fields have N dimension. Pratically, on python code I write:

tree = il.sublink.loadTree(basePath, 135, 11, fields=fields)

I suppose I load the 12th subhalo of snapshot 135 of Illustris-1. If I try to print the SubfindID, the output is an array of dimension N. The first element is "11", like the ID I put in the loadTree function, than there are lot more IDs, reffered to what?to which subhalo?

If I try to print , for example, MainLeafProgenitorID, the output is also a N-dimensional array.

Thanks for helping me

Dylan Nelson
  • 9 May '18

Hi Lara,

Each entry corresponds to a different (earlier) point in time - if you follow the Merger Tree plotting example on the example scripts page, you can see how this looks with e.g. a mass field. The time each entry corresponds to can be figured out from the SnapNum field.

If you load the 'full' tree, this structure might be quite confusing at first, but if you load only the main progenitor branch, this is just a single linear evolution back in time.

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