How to use OR(disjunction) constraint in gurobi ?

[l-outsider]

I have 10 variables(v0, v1, v2, ..., v9), and be outputed from handwritten digit recognition. They are in range [0, 1].

now i need a Vmodel, and variables satisify the following constraints:

v0 >= v7 || v1>=v7 || v2>=v7 || v3>=v7 || v4>=v7 || v5>=v7 || v6>=v7 || v8>=v7 || v9>=v7

how can i use model.addConstr() to add this OR constraint ?

[odow]

1. Use the C API

   Gurobi.jl/src/gen91/libgrb_api.jl

   Lines 209 to 211 in d9cebe4

   	function GRBgetgenconstrOr(model, genconstr, resvarP, nvarsP, vars)
   	ccall((:GRBgetgenconstrOr, libgurobi), Cint, (Ptr{GRBmodel}, Cint, Ptr{Cint}, Ptr{Cint}, Ptr{Cint}), model, genconstr, resvarP, nvarsP, vars)
   	end

2. Reformulate as a MIP:

k = 7
model = Model(Gurobi.Optimizer)
@variable(model, 0 <= v[0:9] <= 1)
@variable(model, z[0:9], Bin)
for i in 0:9
    if i == k
        fix(z[k], 1.0)
    end
    @constraint(model, v[i] + z[i] >= v[k])
end
@constraint(model, sum(z) <= length(z) - 1)

[l-outsider]

@odow
thank you, I sloved this problem by a simple way.

first, create additional 9 binary Vars[9].

then use GenConstrIndicator

for i in range:
    model.addConstr((Vars[i] == 1) >> v[i] >= v[7])

then add constr

model.addConstr(quicksum(Vars) >= 1)
model.addConstr(quicksum(Vars) <= 9)