Julia 函数仅在每次迭代结束时有println（）语句时起作用

我试图从Julia中的a（第212-213页）实现一个3团（三角形）查找算法，但我遇到了代码问题

function find_triangle(graph::AdjacencyListGraphs)

    new_graph = deepcopy(graph)
    sort!(new_graph.edges, by=x->new_graph.D[x], rev=true)
    cliques = Vector{Vector{Int64}}()
    marked_nodes = Set()

    for i in 1:new_graph.n - 2
        cur = new_graph.edges[new_graph.edges.keys[1]]

        # mark vertices adjacent to i
        for j in 1:length(cur)
            push!(marked_nodes,cur[j])
        end

        # search in marked nodes
        for j in 1:length(cur)
            u = cur[j]
            for w in new_graph.edges[u]
                if w in marked_nodes
                    cur_clique = [new_graph.edges.keys[1], u, w]
                    push!(cliques, cur_clique)
                end
            delete!(marked_nodes, u)
            end
        end

        # delete node
        for key in new_graph.edges.keys
            filter!(x->x≠new_graph.edges.keys[1],new_graph.edges[key])
        end
        delete!(new_graph.edges, new_graph.edges.keys[1])

        # this println() call is currently used to prevent an unknown error. Not sure why, but this fixes it
        println(new_graph)
    end

    return cliques
end

该函数的输入如下所示

nodes = [1,2,3,4,5,6]

edges = OrderedDict{Int64, Vector{Int64}}()
edges[1] = [2,3,5]
edges[2] = [1,3,4,6]
edges[3] = [1,2,4,6]
edges[4] = [2,3,5,6]
edges[5] = [1,4]
edges[6] = [2,3,4]

degrees = [3,4,4,4,2,3]
graph = AdjacencyListGraphs(nodes, 6, 10, degrees, edges)
cliques = find_triangle(graph)

图的类型定义如下：

mutable struct AdjacencyListGraphs{Int64}
    vals::Vector{Int64} # vertex list
    n::Int64 # number of vertices
    m::Int64 # number of edges
    D::Vector{Int64} # degree sequence
    edges::OrderedDict{Int64, Vector{Int64}} # adjacency list
end

如果包含println（）语句，函数将正常运行，但如果仅删除该语句，则会遇到以下错误

ERROR: LoadError: KeyError: key 2 not found

在我看来，这个问题似乎是删除节点时出错，println（）语句如何修复它。我之所以需要修复这个问题，是因为我试图在一个大得多的图形上运行代码，该图形包含大约一百万个三角形，但每一步的println（）调用都会使我的计算机崩溃

---

任何帮助都将不胜感激；谢谢大家!

可能某个主体为该自定义类型

邻接柱状图
重写了
println
或
show
，这是我找到的
println
更改代码状态的唯一原因
 问题的原因是您使用了
OrderedDict
的
keys
字段，该字段是私有的。您应该使用访问器功能，例如：

function find_triangle(graph::AdjacencyListGraphs)

    new_graph = deepcopy(graph)
    sort!(new_graph.edges, by=x->new_graph.D[x], rev=true)
    cliques = Vector{Vector{Int64}}()
    marked_nodes = Set()

    for i in 1:new_graph.n - 2
        curk = first(keys(new_graph.edges))
        cur = new_graph.edges[curk]

        # mark vertices adjacent to i
        for j in 1:length(cur)
            push!(marked_nodes,cur[j])
        end

        # search in marked nodes
        for j in 1:length(cur)
            u = cur[j]
            for w in new_graph.edges[u]
                if w in marked_nodes
                    cur_clique = [curk, u, w]
                    push!(cliques, cur_clique)
                end
            delete!(marked_nodes, u)
            end
        end

        # delete node
        for key in new_graph.edges.keys
            filter!(x->x≠curk,new_graph.edges[key])
        end
        delete!(new_graph.edges, curk)

        # this println() call is currently used to prevent an unknown error. Not sure why, but this fixes it
   #     println(new_graph)
    end

    return cliques
end

问题的原因是您删除了字典中的键，但没有调用
rehash在上面。顺便说一句，
rehashprintln
时调用code>，因为它调用
iterate
，而iterate又调用
rehash。因此，这将起作用：

function find_triangle(graph::AdjacencyListGraphs)

    new_graph = deepcopy(graph)
    sort!(new_graph.edges, by=x->new_graph.D[x], rev=true)
    cliques = Vector{Vector{Int64}}()
    marked_nodes = Set()

    for i in 1:new_graph.n - 2
        DataStructures.OrderedCollections.rehash!(new_graph.edges)
        cur = new_graph.edges[new_graph.edges.keys[1]]

        # mark vertices adjacent to i
        for j in 1:length(cur)
            push!(marked_nodes,cur[j])
        end

        # search in marked nodes
        for j in 1:length(cur)
            u = cur[j]
            for w in new_graph.edges[u]
                if w in marked_nodes
                    cur_clique = [new_graph.edges.keys[1], u, w]
                    push!(cliques, cur_clique)
                end
            delete!(marked_nodes, u)
            end
        end

        # delete node
        for key in new_graph.edges.keys
            filter!(x->x≠new_graph.edges.keys[1],new_graph.edges[key])
        end
        delete!(new_graph.edges, new_graph.edges.keys[1])

        # this println() call is currently used to prevent an unknown error. Not sure why, but this fixes it
        #println(new_graph)
    end

    return cliques
end

但是您不应该这样编写代码，而应该使用公共API。
是用户定义的类型吗？你能分享一下它的代码吗？刚刚在帖子中添加了更多信息。抱歉搞混了！您能解释一下它是如何受到
println
的影响吗？昨天，在Juliancon2020期间，我试图解释一下（高级部分）如何快速找到此类问题的根本原因。我将查找它。非常需要资源，顺便说一句，它在我参加的研讨会名单上。但是昨天很忙，很抱歉没有及时回复，但是这很有帮助。非常感谢。