使用Boost多索引搜索多个不良事件 [英] search for multiple indecies with Boost Multi-Index

问题描述

如何通过上一次搜索的结果限制在 boost :: multi_index 中的搜索？
举个例子：假设我有一个内部值为这样的矩形类：

how do I limit the search in a boost::multi_index by the result of a previous search? As an example: suppose I have a rectangle class with an internal value like this:

    class MyRect
    {
    public:
        int    width;  
        int    height; 

        double value;
    }

我需要这种对象的数据结构来回答查询， input_rectangle - 该对象 MyRect 包含在该矩形中并且具有最高值？

and I need a data structure of such object to answer queries like "given an input_rectangle - which object MyRect is contained in that rectangle and has the highest value?"

我可以这样使用一个'multi_index'：

I could use a 'multi_index' like this:

    struct given_value{};
    struct given_width{};
    struct given_height{};

    typedef multi_index_container<MyRect,
        indexed_by<
            ordered_non_unique< tag<given_value>, 
                member<MyRect, double, &MyRect::value>,
            ordered_non_unique< tag<given_width>, 
                member<MyRect, int, &MyRect::width>,
            ordered_non_unique< tag<given_height>, 
                member<MyRect, int, &MyRect::height>, >
        >
    > MyDataStructure;

    typedef MyDataStructure::index<given_width>::type MyDataStructureGivenWidth;
    typedef MyDataStructureGivenWidth::iterator WidthIterator;

如果我的 input_rectangle $ c> input_width 我可以使用这样的：

If my input_rectangle has width input_width I could use something like this:

WidthIterator start_iter = data_object.get<given_width>().begin();
WidthIterator end_iter   = data_object.get<given_width>().upper_bound(input_width);

但是如何通过两个给定的迭代器限制对coresp高度的搜索？
（然后找到该结果中值最高的对象？）

But how do I limit the search for the coresp height by the two given iterators? (And after that find the object with the highest value in that result?)

推荐答案

您可以执行inplace限制。

将匹配宽度查询的结果迭代器存储在另一个容器中，并使用该容器与remove_if查找匹配的高度。

I don't think you can do an inplace limitation.
Store the resulting iterators of the matching widths query in another container and use that container to find the matching heights with remove_if. Then use max_element to find the largest.

如果将元素存储为指针，则可以使用相同的MIC来存储结果。

If you store the elements as pointers, you could use the same MIC to store the results.

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