fixed findmax unconsistency (#521)

* fixed Base.findmax unconsistency

* Update src/ReinforcementLearningCore/src/utils/base.jl

Co-authored-by: Jun Tian <find_my_way@foxmail.com>

Co-authored-by: Jun Tian <find_my_way@foxmail.com>

Author: 3rdCore

src/ReinforcementLearningCore/src/utils/base.jl

@@ -149,8 +149,7 @@ end
 # _rf_findmax((fm, m), (fx, x)) = isless(fm, fx) ? (fx, x) : (fm, m)
 
 # !!! type piracy
-Base.findmax(A::AbstractVector, mask::AbstractVector{Bool}) =
-    findmax(i -> A[i], view(keys(A), mask))
+Base.findmax(A::AbstractVector{T}, mask::AbstractVector{Bool}) where T = findmax(ifelse.(mask, A, typemin(T)))
 
 
 const VectorOrMatrix = Union{AbstractMatrix,AbstractVector}