updated manifest

Author: MartinMikkelsen

docs/Manifest.toml

@@ -11,6 +11,7 @@ QuasiMonteCarlo = "8a4e6c94-4038-4cdc-81c3-7e6ffdb2a71b"
 SpecialFunctions = "276daf66-3868-5448-9aa4-cd146d93841b"
 
 [compat]
+Antique = "0.12.0"
 Optim = "1.7.8"
 Plots = "1.39.0"
 julia = "1.11"

docs/Project.toml

@@ -77,8 +77,13 @@ converged(sol::Solution) = converged(getfield(sol, :convergence))
 
 Per-step target-state energy history — concatenated across stages, or of
 stage `i`.  Ready for plotting (see also `plot(sol)`).
+For a single stage, returns its stored energy history without copying.
 """
-energies(sol::Solution) = reduce(vcat, (s.energies for s in getfield(sol, :stages)))
+function energies(sol::Solution)
+    stages = getfield(sol, :stages)
+    length(stages) == 1 && return only(stages).energies
+    return reduce(vcat, (s.energies for s in stages))
+end
 energies(sol::Solution, i::Integer) = getfield(sol, :stages)[i].energies
 
 function _fmtE(x)