dot#

VarDictND.dot(paramdict)[source]#

Sum the products of variables with corresponding coef from ParamDictND, in an expression.

Assumes the coef to be zero if not found in the ParamDictND.

Equivalent to:

gp.quicksum(paramdict.get(k, 0) * v for k, v in vardict.items())

Parameters:

paramdictParamDictND: ParamDictND to be used for dot product; should have tuple keys of same length as VarDictND.

Returns:

Raises:

TypeError: If the paramdict is not as instance of ParamDictND.
ValueError: If the paramdict does not have tuple keys of same length as VarDictND.

Notes

This method is equivalent to using the matrix multiplication operator @.

Both ParamDictND @ VarDictND and VarDictND @ ParamDictND will also produce the same result.

Examples

Create gurobipy model:

>>> from gurobipy import GRB, Model
>>> mdl = Model()

Create index-set:

>>> arcs = IndexSetND([('A', 'B'), ('B', 'C'), ('C', 'B')], names=['ori', 'des'])

Add variables:

>>> from opti_extensions.gurobipy import addVars
>>> arc_flow = addVars(mdl, arcs, ub=10, vtype=GRB.CONTINUOUS, name='arc-flow')
>>> mdl.update()

Define parameter:

>>> from opti_extensions import ParamDictND
>>> cost = ParamDictND({('A', 'B'): 10, ('B', 'C'): 20})

Compute dot product (three alternative ways):

>>> arc_flow.dot(cost)
<gurobi.LinExpr: 10.0 arc-flow[A,B] + 20.0 arc-flow[B,C] + 0.0 arc-flow[C,B]>

>>> cost @ arc_flow
<gurobi.LinExpr: 10.0 arc-flow[A,B] + 20.0 arc-flow[B,C] + 0.0 arc-flow[C,B]>

>>> arc_flow @ cost
<gurobi.LinExpr: 10.0 arc-flow[A,B] + 20.0 arc-flow[B,C] + 0.0 arc-flow[C,B]>