Deprecate NelderMead better.

src/deprecate.jl

@@ -1 +1 @@
-@deprecate NelderMead(a::Real, g::Real, b::Real) NelderMead(parameters = FixedParameters(a, g, b, 0.5))
+@deprecate NelderMead(a::Real, g::Real, b::Real) NelderMead(initial_simplex = AffineSimplexer(), parameters = FixedParameters(a, g, b, 0.5))

src/nelder_mead.jl

@@ -43,7 +43,24 @@ immutable NelderMead{Ts <: Simplexer, Tp <: NMParameters} <: Optimizer
     parameters::Tp
 end
 
-NelderMead(; initial_simplex = AffineSimplexer(), parameters = AdaptiveParameters()) = NelderMead(initial_simplex, parameters)
+
+function NelderMead(; kwargs...)
+    KW = Dict(kwargs)
+    if any(haskey(KW, k) for k in (:a,:g,:b))
+        a, g, b = 1.0, 2.0, 0.5
+        haskey(KW, :a) && (a = KW[:a])
+        haskey(KW, :g) && (g = KW[:g])
+        haskey(KW, :b) && (b = KW[:b])
+        return NelderMead(a, g, b)
+    elseif any(haskey(KW, k) for k in (:initial_simplex, :parameters))
+        initial_simplex, parameters = AffineSimplexer(), AdaptiveParameters()
+        haskey(KW, :initial_simplex) && (initial_simplex = KW[:initial_simplex])
+        haskey(KW, :parameters) && (parameters = KW[:parameters])
+        return NelderMead(initial_simplex, parameters)
+    else
+        return NelderMead(AffineSimplexer(), AdaptiveParameters())
+    end
+end
 
 # centroid except h-th vertex
 function centroid!{T}(c::Array{T}, simplex, h=0)