trig changes

Author: arnavk23

src/ADNLPProblems/trig.jl

@@ -6,7 +6,11 @@ function trig(; n::Int = default_nvar, type::Type{T} = Float64, kwargs...) where
     for i = 1:n
       s += i * (1 - cos(x[i]))
 
-      for j = max(1, i - 2):min(n, i + 2)
+      js = max(1, i - 2):min(n, i + 2)
+      if iseven(n)
+        js = sort(collect(union(collect(js), [j for j in (i + n ÷ 2, i - n ÷ 2) if 1 <= j <= n])))
+      end
+      for j in js
         aij = 5 * (1 + mod(i, 5) + mod(j, 5))
         bij = (i + j) // 10
         s += aij * sin(x[j]) + bij * cos(x[j])

src/PureJuMP/trig.jl

@@ -20,9 +20,10 @@ function trig(args...; n::Int = default_nvar, kwargs...)
     Min,
     (1 / n) * sum(
       i * (1 - cos(x[i])) +
-      sum(
-        5 * (1 + mod(i, 5) + mod(j, 5)) * sin(x[j]) + (i + j) / 10 * cos(x[j]) for
-        j = max(1, i - 2):min(n, i + 2)
+      (
+        sum(5 * (1 + mod(i, 5) + mod(j, 5)) * sin(x[j]) + (i + j) / 10 * cos(x[j]) for j in (
+          iseven(n) ? sort(collect(union(collect(max(1, i - 2):min(n, i + 2)), [j for j in (i + n ÷ 2, i - n ÷ 2) if 1 <= j <= n]))) : max(1, i - 2):min(n, i + 2)
+        ))
       ) for i = 1:n
     )
   )