Question

I am using python as an interface to several fortran files in my model. I want to duplicate a fortran file several times but at each copy, I will change the parameters that describe my model.

For example: I have the fortran file below

!file.f
! This is a fortran code

!Parameters
alpha = 0.5
beta = 100
...

I want to copy file.f several times such that I will have file1.f, file2.f, file3.f, etc. However, at each file duplicated I want to change the parameters alpha and beta automatically. Thanks

EDIT: Let me explain a little further. I am using python to implement data assimilation (kalman filtering) to models that have already been developed in fortran. Basically, how it works is at each specified time step the fortran models stop running, then I integrate real world data to model data and I do this in python. Then after the integration (assimilation), I rerun the same models however this time using new parameters that I obtained from fusing data from model and observations and the new initial conditions. I use python to do everything except run the model which is being done by fortran.

Answer 1

I think the most consistent way to go would be to use a templating engine. Python has a lot of then, usually deployed within web applications.

But the purpose of templating engines is exactly to allow one to have the bulk of the code, that needs nos change as static text, and through some special markup interpolate that with variables generated within the Python code.

Depending on the complexity of your parameters you could even don’t need any separte templating engine at all, and just go on with Python string formating capabilities, as in the example bellow.

Template engines could provide you with a bit extra capacity, as the ability to unroll loops and conditionals inside the template.

Example – write your fortram template something like:

!file.f
! This is a fortran code

!Parameters
alpha = %(alpha)s
beta = %(beta)s

And in the Python code, write something like:

template = open("fortram_template.for", "rt").read()
data = {"alpha": 0.5, "beta": 100}

with open("fortram_1.for", "wt") as output:
    output.write (template % data)