loading data from csv file

[airsq...@gmail.com]

Hello-

I'm trying to reconcile the best way to load bunches of table data into a Pyomo model from .csv files.

I note that the import command can be buried in another data file, but I can't get that working properly... and I note that import is deprecated in favor of load, but I can't see any options for pointing the load command at a csv file ...?  

any ideas?

I have something like this in a toy model:

m = AbstractModel()

m.A = Set(initialize=['ddg', 'lcs', 'ffg'])

m.Cost = Param(m.A)

m.Time = Param(m.A)

data = DataPortal()

data.load ????

and a csv file that has something like this:  (first column is index, second and third are parameter values):

A,Cost,Time

ddg,5.6,5

lcs,6.7,8

ffg,8,9

I'm considering shifting gears and using csv reader in core python to load these, but peeling out the multiple parameters from columnar data seems like a pain.

[Andres Collart]

Hi,

I usually use Pandas to create dictionaries and then import those dictionaries into Pyomo via the initialize function. Hope that helps.

-Andres

[aMRo alHarBi]

Hi Andres ,

I'm trying to solve the Transport problem, I made a xls_to_pyomo.py file other than the model file (transport.py) to extract the data from xls to lists and dictionaries that match the one in the example. but I don't know how to use the initialize function to call them. also, do I have to import the file xls_to_pyomo.py at the beginning of the model ?

for example : 

in the transpoert.py they used this to define model.i : model.i = Set(initialize=['seattle','san-diego'], doc='Canning plans')

I made a list called plans in xls_to_pyomo.py ( plans=['seattle','san-diego']. ). how should i call this list in transport.py

Also, in the transpoert.py in order to define model.d they made a dictionary in the model file called  dtab and used this line to define model.d : model.d = Param(model.i, model.j, initialize=dtab, doc='Distance in thousands of miles').

again how do I call my dictionary that matches dtab but from xls_to_pyomo.py

Thanks!

[Andres Collart]

Hi Amro,

Unforunately Im travelling and only have my phone to respond with, thus no code snippets to really help.

Yes you do need to import xls_to_pyomo. In xls_to_pyomo.py, if you've defined a function that carries out the task of getting the dictionaries and returns those then it's as easy as including at the top of transport.py the following:

from xls_to_pyomo import myfunction as myfunction
Dict1,dict2,...,dict10= myfunction()

Then you can use those dictionaries in transport.py.

Let me know if there's anything else I can help with. Best of luck.

-Andres

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[aMRo alHarBi]

Yeah, that works..! Thanks :) 

but it seems to work only in terminal, what it I want it to work in python using : 

if __name__ == '__main__':

    # This emulates what the pyomo command-line tools does

    from pyomo.opt import SolverFactory

    import pyomo.environ

    opt = SolverFactory("gurobi")

    results = opt.solve(model)

    #sends results to stdout

    results.write()

    print("\nDisplaying Solution\n" + '-'*60)

    pyomo_postprocess(None, instance, results)

--

Regards,

Amro Alharbi

[Andres Collart]

That seems like it should work to me. Maybe there are issues with the Gurobi path not being properly set. Hopefully someone else can help in that area.

Best of luck.

Cheers,

Andres

Andres Collart
ca.linkedin.com/in/andrescollart/