Solving a concrete model example

[omowunmiayo]

Please I need help with running the attached pyomo file. I am new to using pyomo. I tried using it to run  a simple Electricity Transmission expansion problem using the concrete model and got the following errors which I am not sure of how to solve.

ERROR: Constructing component 'f' from data=None failed:
        KeyError: "Error accessing indexed component: Index '0' is not valid for array component 'li_f_inv'"

Please what do you think needs corrections?

Thank you

[Watson, Jean-Paul]

The issue is that the variable “li_f_invz” is indexed by both model.E and model.LI. So at a minimum, you need to supply a tuple when indexing elements of li_f_inv.

 

jpw

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[omowunmiayo]

Hi JPW,

Thanks for your prompt response. I think that was what I specified (within the bounds) as in:

def fl_inv(model, i, l):
    return (0, model.li_max_f)
model.li_f_inv = Var(model.E, model.LI, bounds = fl_inv)

where model_li_max_f was specified earlier in the code.

or can you give me an example please?

Thank you.

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[Watson, Jean-Paul]

Your issue has nothing to do with li_max_f, to be clear.

 

At least one issue comes into play when you define fl_rule. Here, you are indexing the variable li_f_inv by the index “l”. But “l” is an element of the set model.E. And you need to index li_f_inv with a tuple, e.g., li_f_inv[j,l].  

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[omowunmiayo]

Thank you. I tried what you suggested and it replaced with tuples where necessary. as in:

def fl_rule(model, j, l):
    total_f = (model.li_f_inv[j, l] + model.li_f[l])
    return (- total_f[j], total_f[j])
model.f = Var(model.LI, model.E, initialize = 0, bounds = fl_rule)

I also corrected it in the objective function. I got the following error message:

ERROR: Constructing component 'f' from data=None failed:

        KeyError: "Error accessing indexed component: Index '('L3', 0)' is not valid for array component 'li_f_inv'"

could it be in assigning the string values to set.LI?

Looking forward to your response. Apologies for the stress.

Thank you

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[Watson, Jean-Paul]

You can add a line after constructing a component, e.g., as follows:

 

print(list(iterkeys(model.li_f_inv)))

 

You’ll see that the valid indices for li_f_inv are: [(0, 'L2'), (0, 'L1'), (0, 'L3'), (1, 'L2'), (1, 'L1'), (1, 'L3'), (2, 'L2'), (2, 'L1'), (2, 'L3'), (3, 'L2'), (3, 'L1'), (3, 'L3')]

 

In this case, you have an ordering issue between model.LI and model.E.

 

The above fragment will help diagnose model index issues in general.

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[omowunmiayo]

Dear JPW,

Thanks for your response. I tried that but didn't get the indices. instead got the error:

NameError: name 'iterkeys' is not defined

Not sure what to do next. Thanks

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[Watson, Jean-Paul]

I was using Python 3.X – you’ll need to Google the equivalent for Python 2.7.

[omowunmiayo]

Dear JPW,

Thank you for your last response. I was able to get around that problem. But moving ahead I got the following error messages when I tried running the updated codes attached.

ERROR: Rule failed when generating expression for constraint line_equation with index ('L2', 0):
        TypeError: Cannot convert object of type 'generator' (value = <generator object line_equation.<locals>.<genexpr> at 0x000001B6F840E360>) to a numeric value.
ERROR: Constructing component 'line_equation' from data=None failed:
        TypeError: Cannot convert object of type 'generator' (value = <generator object line_equation.<locals>.<genexpr> at 0x000001B6F840E360>) to a numeric value.

what do you suggest might be a good solution please? Looking forward to your response. Thanks for your help so far.

Kind Regards

Olayinka Ayo

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[omowunmiayo]

Hi JPW,

I am having an Index error message on the following attached concrete model. I am unable to trace the error. Please can you help?

The error message is as follows:

ERROR: Rule failed when generating expression for constraint SystemBalance with index (0, 'N3'):
        IndexError: invalid index
ERROR: Constructing component 'SystemBalance' from data=None failed:
        IndexError: invalid index

Looking forward to your response. Thank you

[Jiberu Ba]

Dear JPW and Watson

Thank you very much for this helpful information about transmission expansion planning. 

I need your support because I new using Pyomo for transmission expansion planning problem. Can you share with some optimization of TEP model? 

Best wishes

Jiberu

[Jean-Paul Watson]

Hi Jiberu,

We unfortunately don't have any publicly available TEP models in Pyomo.

Jean-Paul

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