Utility-Functions-Modelling

##Common functions that may be referenced in other ipython notebooks

This repository contains a number of ipython notebook files (.ipynb) each containing a single cell with a number of functions defined in each. The work flow for using these functions (using EvapotranspirationFunctions.ipynb as an example) is as follows:

• Clone the Utility-Functions-Moedlling repository to your computer
• Open the EvapotranspirationFunctions.ipynb notebook.
• Edit the first line in the note book so the write file expression points to the location of the library dirrectory of your anaconda instilation
• For me the first line looks like this

%%writefile C:\Anaconda\Lib\ETFunctions.py

• Runing this cell will create a ETFunctions.py file in the right place for it to be referenced by other Ipython notebooks
• In the note book where you want to uses these functions load them as:

import ETFunctions

• Then call them as, for example:

ETFunctions.PenmanEO()

• Tab completion will bring up all the functions available in that library
• Shift+Tab to the right of the first bracket in the function brings up the arguments the function needs and the contents of the funtions docstring (docummentation, see below for more detail on documenting functions)

To edit the content of these functions:

• Simply change the content of the cell in the note book, either fixing errors in functions or adding new ones.
• When the changes are complete run the script to update the .py file in the library.
• Close ipython notebooks and reopen for the changes to take effect in your notebooks.
• Push any changes into the master repo so they are available to all

To add new functin libaries:

• Create a new note book with the appropriate functions and %%writefile magic

###Adding and updating docummntation to functions A docstring attribute should be added to each function describing what it does, what its arguements are and what units the return and the arguements are in. This is doen by adding a text string the line below the function decleration. As below:

def nett_radiation(total_radiation):
    """Net solar radiation (MJ/m2) which is total incomming radiation less that which is reflected.
    
    This function is taken from Jamieson P. 1982. Comparision of methods of estimating maximum 
    evapotranspiration from a barley crop. New Zealand Journal of Science, 25: 175-181.
    
    Args:
        total_radiation: Total incoming solar radiation (Units MJ/M2/day)
    
    Returns:
        Value of net solar radiation
    """
    _ret = None
    _ret = - 0.25 + 0.59 * total_radiation
    return _ret

For the docstring to be added or updated the cell containing the function must be run. %%writefile majic just writes the contents of the cell withing out running all that is below. Thus if docummentation is added or changed for a function the %%writefile line should be commented out and the cell containing the functions run before uncommenting the %%writefile majic and running the cell again to create the function library with upto date documentation on the functions