pyomo / pyomogallery

A collection of Pyomo examples

PyomoGallery

A collection of Pyomo examples

For Users

This project supports a collection of Pyomo models and scripting examples. See the wiki for the list of examples.

The Pyomo Gallery is available under the BSD License.

For Contributors

We encourage contributions to the Pyomo Gallery from all Pyomo users and developers. Each example in the gallery is stored in a separate subdirectory, and a Jupyter notebook is used to describe the example. Existing examples illustrate the expected level of detail, but feel free to structure your example in a different manner as appropriate.

By contributing to this software project, you are agreeing to the following terms and conditions for your contributions:

1. You agree your contributions are submitted under the BSD license.
2. You represent you are authorized to make the contributions and grant the license. If your employer has rights to intellectual property that includes your contributions, you represent that you have received permission to make contributions and grant the required license on behalf of that employer.

pyomogallery's Issues

Conclusion in transport.ipynb

Hello Pyomos!

where do you take the 50 cases from Seattle to New-York from in your conlusion?

Solution Information Variable: x[seattle,chicago]: Value: 300 x[san-diego,topeka]: Value: 275 x[san-diego,new-york]: Value: 325 Constraint: No values

This solution shows that the minimum transport costs is attained when 300 cases are sent from the Seattle plant to the Chicago market, 50 cases from Seattle to New-York and 275 cases each are sent from San-Diego plant to New-York and Topeka markets.

Add a test script

I think we should add a simple test script that executes each of the examples and makes sure that no error occurs during execution. IMO, attempting to test anything beyond this (e.g., an output baseline) would require too much work on the part of contributors.

There are two issues that I can think of that complicate this:

1. How do we execute an example?

   I think the answer is that for each example, we convert the .ipynb file into a temporary script using the the commnd: jupyter nbconvert --to script [filename].ipynb. As long is we can install jupyter on Travis, this seems like a straightforward thing to do.

2. When do these tests get executed?

   Obviously, when someone pushes a new example to this repo. However, we really want to be testing after pushes to the Pyomo/pyomo master branch, just like we should be testing Pyomo/pyomo after pushes to Pyutilib/pyutilib master. It looks like we are currently not doing this (with Travis / Appveyor at least), so it makes me think it is not currently possible. @whart222, @jsiirola : Do either of you know if this is possible?

   I suppose it's also reasonable that we only test examples against the latest Pyomo release. Thoughts?

unable to write complex constraint in pyomo

I am trying to write the following constraint in pyomo:

The description is as follows:

ū ∈ Nf=Nodes from a set Gf

u ∈ Ns=Nodes from a set Gs

Φf=binary variable indicating 1 if the node ū from Nf can be deployed on u from Ns, otherwise 0.

Df cpu ū = demand (CPU parameter) of node ū.

a cpu u = available ratio of node u (ratio = capacity-demand).

C cpu u = capacity (CPU parameter) of node u.

model = ConcreteModel() 
model.nf = (['VNF1', 'VNF2', 'VNF3'])
model.ns = (['S1', 'S2', 'S3'])

model.fi = Var(model.nf, model.ns, within=Binary)

model.Dcpu = Param(model.nf, within=NonNegativeReals, initialize=1)

model.Ccpu = Param(model.ns, within=NonNegativeReals, initialize=5)

def acpu_rule(model, ns, nf): 
      return (model.Ccpu[ns]/model.Dcpu[nf])
model.acp=Param(model.ns, model.nf, initialize=acpu_rule)

model.c1 = Constraint(sum(model.fi[ub, u] for ub in model.nf for u in model.ns * model.Dcpu[ub] for ub in model.nf) <= model.Ccpu[u] for u in model.ns) * model.acp[ub] for ub in model.nf)

For a long, I am receiving different errors and I am unable to locate the problem.

Currently, I am getting the 'TypeError: unhashable type: 'InequalityExpression' ' error.

Please help me to get out of this.

Regards

diet.py example seems to be broken

When I run the diet.py example I get an error:

$ pyomo solve --solver=glpk diet.py diet.dat || echo fail
[    0.00] Setting up Pyomo environment
[    0.00] Applying Pyomo preprocessing actions
[    0.00] Creating model
ERROR: Rule failed when generating expression for constraint nutrient_limit
    with index Cal: PyomoException: Cannot convert non-constant expression to
    bool. This error is usually caused by using an expression in a boolean
    context such as an if statement. For example,
        m.x = Var() if m.x <= 0:
            ...
    would cause this exception.
ERROR: Constructing component 'nutrient_limit' from data=None failed:
        PyomoException: Cannot convert non-constant expression to bool. This
        error is usually caused by using an expression in a boolean context
        such as an if statement. For example, m.x = Var() if m.x <= 0:
            ...
    would cause this exception.
[    0.02] Pyomo Finished
ERROR: Unexpected exception while running model:
        Cannot convert non-constant expression to bool. This error is usually
        caused by using an expression in a boolean context such as an if
        statement. For example, m.x = Var() if m.x <= 0:
            ...
    would cause this exception.
errorcode: 1
$ pyomo --version
Pyomo 6.0.1 (CPython 3.7.10 on Darwin 18.7.0)

Requirements

Hello there !

I've tried to run some examples here ... and I think that by now a requirements.txt file is necessary.
Looks like there are things outdated in pandas and also pyomo.

The following command seem to work, but you need to change all pandas .ix methods to .loc

pip3 install wheel pandas "pyomo<6" ipykernel

After adding this requirements and fixing the pandas issues ... maybe updating the codes to the new pyomo would be interesting as well.

Gams $ convert to Pyomo

There is any effective way to convert right dollar of gams to pyomo?
For example
vr(t) = tr*sr*sum(a$(ord(t)+ord(a) gt card(t)), yv(a)*delta(a));
thx

Error with symbol_map creation in asl_io.write.write_nl

On attempt to run simplest example in asl_io.write I have an error
AttributeError: 'float' object has no attribute 'model'
The error occurs in line #28 of write.py in preparing symbol_cuid_pairs .
I use Python 3.11.4 (miniconda) and Pyomo 6.7.1
It is the first time when I see this error on using Pyomo and your excellent asl_io functions. Bad news is that I have got the same error and with other Pyomo models...

Example Notebooks do not Open

When trying to access the example problems I get the following redirect notice:

Question on the Flow Example

Hi, I am not sure why you included (or multiplies) the arc capacity by the flow in the objective function of the flow network example.

Network interdiction problems are broken

I get the following error when I try to run, e.g., the min_cost_flow_interdict example:

`MultiIndex([( 'B', 'End'),
( 'C', 'B'),
( 'C', 'D'),
( 'D', 'End'),
('Start', 'B'),
('Start', 'C')],
names=['StartNode', 'EndNode'])
ERROR: Constructing component 'edge_set' from data=None failed: ValueError:
The truth value of a MultiIndex is ambiguous. Use a.empty, a.bool(),
a.item(), a.any() or a.all().

ValueError Traceback (most recent call last)
in
227
228 if name == 'main':
--> 229 m = MinCostFlowInterdiction('sample_nodes_data.csv', 'sample_arcs_data.csv')
230 m.solve()
231 m.printSolution()

in init(self, nodefile, arcfile, attacks)
44 self.nCmax = len(self.node_set) * self.arc_data['Cost'].max()
45
---> 46 self.createPrimal()
47 self.createInterdictionDual()
48

in createPrimal(self)
59 # Add the sets
60 model.node_set = pe.Set( initialize=self.node_set )
---> 61 model.edge_set = pe.Set( initialize=self.arc_set, dimen=2)
62
63 # Create the variables

C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\pyomo\core\base\block.py in setattr(self, name, val)
541 # Pyomo components are added with the add_component method.
542 #
--> 543 self.add_component(name, val)
544 else:
545 #

C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\pyomo\core\base\block.py in add_component(self, name, val)
1079 _blockName, str(data))
1080 try:
-> 1081 val.construct(data)
1082 except:
1083 err = sys.exc_info()[1]

C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\pyomo\core\base\util.py in construct(self, data)
123 self._name = base.name
124 self.class = base
--> 125 return base.construct(self, data)
126 construct.doc = base.construct.doc
127 cls.construct = construct

C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\pyomo\core\base\set.py in construct(self, data)
1987 # Bypass the index validation and create the member directly
1988 for index in self.index_set():
-> 1989 self._getitem_when_not_present(index)
1990 finally:
1991 # Restore the original initializer (if overridden by data argument)

C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\pyomo\core\base\set.py in _getitem_when_not_present(self, index)
2030 self._init_values._dimen = _d
2031 try:
-> 2032 _values = self._init_values(_block, index)
2033 except TuplizeError as e:
2034 raise ValueError( str(e) % (

C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\pyomo\core\base\set.py in call(self, parent, index)
412 elif _val is Set.Skip:
413 return _val
--> 414 elif not _val:
415 return _val
416

C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\pandas\core\indexes\base.py in nonzero(self)
2148 def nonzero(self):
2149 raise ValueError(
-> 2150 f"The truth value of a {type(self).name} is ambiguous. "
2151 "Use a.empty, a.bool(), a.item(), a.any() or a.all()."
2152 )

ValueError: The truth value of a MultiIndex is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().`