How to use a dict for .start?
Answered
Hello, I have the following dict, which I would like to use as a start solution for my MIP. Unfortunately, I haven't quite figured out what the correct code for this would be. The dict reflects the indices \(i,t,j\) The variable tyredeg is to be filled with the start values. It is defined as:
tyredeg = m.addVars(I, T, J, vtype=gu.GRB.CONTINUOUS, lb=0, ub=1, name="deg")
Thanks in advance.
The dict:
{(1, 1, 1): 0.0, (1, 1, 2): 0.0, (1, 1, 3): 0.0, (1, 2, 1): 0.0, (1, 2, 2): 0.0, (1, 2, 3): 0.0, (1, 3, 1): 1.0, (1, 3, 2): 0.0, (1, 3, 3): 0.0, (1, 4, 1): 1.0, (1, 4, 2): 0.0, (1, 4, 3): 0.0, (1, 5, 1): 1.0, (1, 5, 2): 0.0, (1, 5, 3): 0.0, (1, 6, 1): 1.0, (1, 6, 2): 0.0, (1, 6, 3): 0.0, (1, 7, 1): 1.0, (1, 7, 2): 0.0, (1, 7, 3): 0.0, (1, 8, 1): 0.0, (1, 8, 2): 0.0, (1, 8, 3): 0.0, (1, 9, 1): 0.0, (1, 9, 2): 0.0, (1, 9, 3): 0.0, (1, 10, 1): 1.0, (1, 10, 2): 0.0, (1, 10, 3): 0.0, (1, 11, 1): 1.0, (1, 11, 2): 0.0, (1, 11, 3): 0.0, (1, 12, 1): 1.0, (1, 12, 2): 0.0, (1, 12, 3): 0.0, (1, 13, 1): 1.0, (1, 13, 2): 0.0, (1, 13, 3): 0.0, (1, 14, 1): 1.0, (1, 14, 2): 0.0, (1, 14, 3): 0.0, (2, 1, 1): 0.0, (2, 1, 2): 0.0, (2, 1, 3): 1.0, (2, 2, 1): 0.0, (2, 2, 2): 0.0, (2, 2, 3): 1.0, (2, 3, 1): 0.0, (2, 3, 2): 0.0, (2, 3, 3): 1.0, (2, 4, 1): 0.0, (2, 4, 2): 0.0, (2, 4, 3): 1.0, (2, 5, 1): 0.0, (2, 5, 2): 0.0, (2, 5, 3): 1.0, (2, 6, 1): 0.0, (2, 6, 2): 0.0, (2, 6, 3): 0.0, (2, 7, 1): 0.0, (2, 7, 2): 0.0, (2, 7, 3): 0.0, (2, 8, 1): 0.0, (2, 8, 2): 0.0, (2, 8, 3): 1.0, (2, 9, 1): 0.0, (2, 9, 2): 0.0, (2, 9, 3): 1.0, (2, 10, 1): 0.0, (2, 10, 2): 0.0, (2, 10, 3): 1.0, (2, 11, 1): 0.0, (2, 11, 2): 0.0, (2, 11, 3): 1.0, (2, 12, 1): 0.0, (2, 12, 2): 0.0, (2, 12, 3): 1.0, (2, 13, 1): 0.0, (2, 13, 2): 0.0, (2, 13, 3): 0.0, (2, 14, 1): 0.0, (2, 14, 2): 0.0, (2, 14, 3): 0.0, (3, 1, 1): 1.0, (3, 1, 2): 0.0, (3, 1, 3): 0.0, (3, 2, 1): 0.0, (3, 2, 2): 0.0, (3, 2, 3): 0.0, (3, 3, 1): 0.0, (3, 3, 2): 0.0, (3, 3, 3): 0.0, (3, 4, 1): 1.0, (3, 4, 2): 0.0, (3, 4, 3): 0.0, (3, 5, 1): 1.0, (3, 5, 2): 0.0, (3, 5, 3): 0.0, (3, 6, 1): 1.0, (3, 6, 2): 0.0, (3, 6, 3): 0.0, (3, 7, 1): 1.0, (3, 7, 2): 0.0, (3, 7, 3): 0.0, (3, 8, 1): 1.0, (3, 8, 2): 0.0, (3, 8, 3): 0.0, (3, 9, 1): 0.0, (3, 9, 2): 0.0, (3, 9, 3): 0.0, (3, 10, 1): 0.0, (3, 10, 2): 0.0, (3, 10, 3): 0.0, (3, 11, 1): 1.0, (3, 11, 2): 0.0, (3, 11, 3): 0.0, (3, 12, 1): 0.0, (3, 12, 2): 0.0, (3, 12, 3): 0.91, (3, 13, 1): 0.0, (3, 13, 2): 0.0, (3, 13, 3): 0.91, (3, 14, 1): 0.0, (3, 14, 2): 0.0, (3, 14, 3): 0.91}
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Hi Dejan,
You could set the .Start attribute with the following code:
for key, value in start_dict.items():
tyredeg[key].Start = valueHowever Start values are only valid for integer (including binary) variables, so this code will not have the effect you want it to.
We do have PStart which can be used with continuous variables (the values must be provided for every variable), but it also needs to be used in conjunction with DStart which is related to constraints.
- Riley
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