correct CMAES default params

src/cmaes.jl

@@ -24,20 +24,22 @@ struct CMAES{T} <: AbstractOptimizer
     cₘ::T
     wᵢ::Vector{T}
 
-    function CMAES(; μ::Int=15, λ::Int=2μ, mu::Int=μ, lambda::Int=2mu, weights::Vector{T}=zeros(lambda),
+    function CMAES(; μ::Int=15, λ::Int=2μ, mu::Int=μ, lambda::Int=0, weights::Vector{T}=zeros(lambda),
                      c_1::Real=NaN, c_c::Real=NaN, c_mu::Real=NaN, c_sigma::Real=NaN,
                      sigma0::Real=1, c_m::Real=1) where {T}
         @assert c_m ≤ 1 "cₘ > 1"
+        if lambda == 0
+            lambda = μ == mu ? λ : 2*mu
+            weights = zeros(lambda)
+        end
         @assert length(weights) == lambda "Number of weights must be $lambda"
         new{T}(mu, lambda, c_1, c_c, c_mu, c_sigma, sigma0, c_m, weights)
     end
 end
-
 population_size(method::CMAES) = method.μ
 default_options(method::CMAES) = (iterations=1500, abstol=1e-15)
 summary(m::CMAES) = "($(m.μ),$(m.λ))-CMA-ES"
 
-
 mutable struct CMAESState{T,TI} <: AbstractOptimizerState
     N::Int
     μ_eff::T