I would register constraint somehow like `c1`

as a user-defined function

```
using Ipopt
using JuMP
using MathOptInterface
const MOI = MathOptInterface
d1 = 4
d2 = 5
d3 = 6
para_a = rand(d3)
m = Model(optimizer_with_attributes(Ipopt.Optimizer))
@variable(m, uc[i in 1:d1, j in 1:d2, k in 1:d3])
@variable(m, v[i in 1:d1, k in 1:d3])
@variable(m, w[i in 1:d1, j in 1:d2, k in 1:d3,])
@NLconstraint(m, c1[i in 1:d1, j in 1:d2, k in 1:d3], uc[i, j, k] == v[i, k] + sum(w[i, j, s] * para_a[s] for s in 1:d3))
```

I tried to implement it and got errors as below.

```
function f(uc_, v_, w_...)
v_ + sum(w_[k] * para_a[k] for k in 1:length(w_)) - uc_
end
register(m, :f, 2 + d3, f,autodiff=true)
@NLconstraint(m, c2[i in 1:d1, j in 1:d2, k in 1:d3], f(uc[i, j, k], v[i, k], w[i, j, 1:d3]...) == 0)
ERROR: Unexpected expression in f(uc[i, j, k], v[i, k], w[i, j, 1:d3]...). JuMP supports splatting only symbols. For example, x... is ok, but (x + 1)..., [x; y]... and g(f(y)...) are not.
```

It seems that only a symbol can be used in user-defined function.

Is there any way to use a subarray like `w[i, j, :]`

args?