Hello everyone,

I am pleased to announce the release of ytree version 1.1.

ytree is a merger-tree code with yt-like syntax for loading data and
accessing fields.  ytree can:

* return tree and halo data fields with symbolic units like in yt

* create merger-trees for Gadget FoF/Subfind catalogs

* load merger-trees from Rockstar halo catalogs and consistent-trees

* save individual and collections of merger-trees into a reloadable

As of ytree version 1.1, field access is even more yt-like.

>>> import ytree
>>> a = ytree.load("tree_0_0_0.dat") # consistent-trees

>>> # masses for roots of all trees
>>> print (a["mvir"].to("Msun"))
[  1.65035971e+13,   1.43309353e+13,   5.18129496e+14, ...
   3.47482014e+12,   1.30273381e+12,   3.47482014e+12] Msun

>>> # mass for the root of the first tree
>>> print (a[0]["mvir"])
11470000000000.0 Msun/h

>>> # most massive progenitors for first tree
>>> print (a[0]["line", "mvir"])
[  1.14700000e+13,   1.20700000e+13,   1.23700000e+13, ...
   3.32000000e+12,   1.20700000e+12,   2.71600000e+12] Msun/h

ytree is compatible with both Python 2 and 3 and can be installed with
pip as:

pip install ytree

For more information, please visit:

ytree is an open-source project.  If you're interested in
contributing, please do!