Sorry, I meant:
Base.isless(s1::State, s2::State) = isless(s1.a, s2.a) || (s1.a == s2.a &&
isless(s1.b, s2.b))
On Friday, January 8, 2016 at 7:56:51 PM UTC+9, Kenta Sato wrote:
>
> The priority queue in Base is different from priority queues in other
> languages.
> I think you can use a plain priority queue (or heap) defined the
> DataStructures.jl package.
> To pair priority and state, `priority => state` would be helpful. This
> paired values are ordered by the first element (priority) and then the
> second element (state). So you can push and pop according to the priority.
>
> Here is an example:
>
> julia> Base.isless(s1::State, s2::State) = isless(s1.a, s1.a) || (s1.a ==
> s2.b && isless(s
> 1.a, s2.b))
> isless (generic function with 32 methods)
>
>
> julia> h = binary_minheap(Pair{Int,State})
> DataStructures.BinaryHeap{Pair{Int64,State},DataStructures.LessThan}(
> DataStructures.LessTh
> an(),Pair{Int64,State}[])
>
>
> julia> push!(h, 4 => State(5, 3))
>
>
> julia> push!(h, 2 => State(5, 3))
>
>
> julia> top(h)
> 2=>State(5,3)
>
>
> julia> pop!(h)
> 2=>State(5,3)
>
>
> julia> top(h)
> 4=>State(5,3)
>
>
>
> On Friday, January 8, 2016 at 6:32:11 PM UTC+9, Tomas Lycken wrote:
>>
>> I tried this today:
>>
>> immutable State
>> a::Int
>> b::Int
>> end
>>
>> import Base.Collections: PriorityQueue, enqueue!, dequeue!, peek
>>
>> pq = PriorityQueue(Int,Int)
>>
>> enqueue!(pq, State(5,3), 4)
>> enqueue!(pq, State(5,3), 2)
>>
>> but it fails with the error
>>
>> LoadError: ArgumentError: PriorityQueue keys must be unique
>>
>> I assume this is because the states are immutable, and thus compare equal
>> if all their values compare equal. Is there a way to make a priority queue
>> insert the same state on several priorities, i.e. to support my example
>> above?
>>
>> // T
>>
>>
>
