This [script](https://osf.io/ktj89) solves the coupled linear ODEs for a directed, acyclic network.
To use, first download the file by typing
**curl -o ode_dag_network.py -J -L https://osf.io/ktj89/download**
Use the script on an input Webnucleo XML file (in this example, called *net.xml*). To obtain an [example](https://osf.io/zhrfn/), type
**curl -o net.xml -J -L https://osf.io/kyhbs/download**
Then solve, for example, a beta-decay chain problem by typing
**python ode_dag_network.py net.xml "{sn160; 1}" out.xml --nuc_xpath "[(a=1) or (a >= 140 and a <= 160)]" --reac_xpath "[(product = 'electron')]" --t_end 100 --N_steps=101 --time_scaling logarithmic --t_start 1.e-5**
The output is contained in the Webnucleo XML file *out.xml*.