# Ipopt solver: no method matching setvartype!

**URL:** <https://discourse.julialang.org/t/ipopt-solver-no-method-matching-setvartype/11091>\
**Category:** Optimization (Mathematical)\
**Created:** [May 23, 2018, 7:26am UTC](https://discourse.julialang.org/t/ipopt-solver-no-method-matching-setvartype/11091 "2018-05-23T07:26:28Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![tfk17lstm](https://avatars.discourse-cdn.com/v4/letter/t/f0a364/32.png) [@tfk17lstm](https://discourse.julialang.org/u/tfk17lstm)\
**Post date:** [May 23, 2018, 7:26am UTC](https://discourse.julialang.org/t/ipopt-solver-no-method-matching-setvartype/11091/1 "2018-05-23T07:26:28Z")

</div>

Dear colleagues, I was using juliabox (because for the moment I can no install solvers in my julia) and I am using the same model that I use for my model with linear costs. This is the model:

```julia
#dispatch with quadratic cost function
dispatchQ = Model(solver=IpoptSolver())

# define variables
@variable(dispatchQ, p[1:nGen, 1:T] >= 0) #power
@variable(dispatchQ, u[1:nGen, 1:T], Bin) #binary for SC-SD
@variable(dispatchQ, s[1:nGen, 1:T] >= 0) #normal startup

# objective is to minimize total cost
@objective(dispatchQ, Min, sum(c[j]*p[j,t]*p[j,t]+b[j]*p[j,t]+a[j]+s[j,t] for j = 1:nGen for t = 1:T))

# power balance
@constraint(dispatchQ, consPowerBalance[t=1:T], sum(p[j,t] for j = 1:nGen) == L[t])

# variable Pmax and Pmin
@constraint(dispatchQ, consPMax[j=1:nGen, t=1:T], p[j,t] <= PMax[j,t] * u[j,t])
@constraint(dispatchQ, consPMin[j=1:nGen, t=1:T], p[j,t] >= PMin[j,t] * u[j,t])

# simplified startup costs
@constraint(dispatchQ, conss1[j=1:nGen, t=1], s[j,t] >= d[j] * (u[j,t] - X0[j]))
@constraint(dispatchQ, conss2[j=1:nGen, t=2:T], s[j,t] >= d[j] * (u[j,t] - u[j,t-1]))

# print model (do not be afraid)
print(dispatchQ)

# save the status
status = solve(dispatchQ)

```

The model is printed but when the code arrives to the solver part I get this error:

```julia
MethodError: **no method matching setvartype!** (::Ipopt.IpoptMathProgModel, ::Array{Symbol,1})
Closest candidates are:
  setvartype!(::MathProgBase.SolverInterface.NonlinearToLPQPBridge, ::Array{Symbol,1}) at /home/jrun/.julia/v0.6/MathProgBase/src/SolverInterface/nonlinear_to_lpqp.jl:88
  setvartype!(::MathProgBase.SolverInterface.ConicToLPQPBridge, ::Any) at /home/jrun/.julia/v0.6/MathProgBase/src/SolverInterface/conic_to_lpqp.jl:318
  setvartype!(::MathProgBase.SolverInterface.LPQPtoConicBridge, ::Any) at /home/jrun/.julia/v0.6/MathProgBase/src/SolverInterface/lpqp_to_conic.jl:273

Stacktrace:
 [1] optimize!(::MathProgBase.SolverInterface.NonlinearToLPQPBridge) at /home/jrun/.julia/v0.6/MathProgBase/src/SolverInterface/nonlinear_to_lpqp.jl:69
 [2] #solve#116(::Bool, ::Bool, ::Bool, ::Array{Any,1}, ::Function, ::JuMP.Model) at /home/jrun/.julia/v0.6/JuMP/src/solvers.jl:175
 [3] solve(::JuMP.Model) at /home/jrun/.julia/v0.6/JuMP/src/solvers.jl:150

```

Is something related with the variables supported? Does Ipopt not support binary variables?

---

<div class="post-metadata">

**Author:** ![odow](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/odow/32/28685_2.png) [@odow](https://discourse.julialang.org/u/odow)\
**Post date:** [May 23, 2018, 11:45pm UTC](https://discourse.julialang.org/t/ipopt-solver-no-method-matching-setvartype/11091/2 "2018-05-23T23:45:29Z")

</div>

Ipopt doesn’t support binary variables. You may want to have a look at using [Gurobi](https://github.com/JuliaOpt/Gurobi.jl/), [CPLEX](https://github.com/JuliaOpt/CPLEX.jl/), or [Pajarito.jl](https://github.com/JuliaOpt/Pajarito.jl) instead.