Re: [boost] How to use mutable_queue with non basic types

Subject: Re: [boost] How to use mutable_queue with non basic types
From: Emili Hernàndez (emilihb_at_[hidden])
Date: 2010-04-12 10:09:48

Jeremiah Willcock escribió:
> On Mon, 12 Apr 2010, Emili Hernàndez wrote:
>
>> Jeremiah Willcock escribió:
>>> On Fri, 9 Apr 2010, Emili Hernàndez wrote:
>>>
>>>> Hi all,
>>>>
>>>> I've used mutable_queue with basic types (double and int) with no
>>>> problem.
>>>> Now I trying to do it with my own type:
>>>>
>>>> typedef MyObject entry_t;
>>>> typedef vector<entry_t> storage_t;
>>>> typedef MySortingCriterion comp_t;
>>>> typedef boost::identity_property_map prop_map_t;
>>>> typedef boost::mutable_queue<entry_t, storage_t, comp_t, prop_map_t>
>>>> queue_t;
>>>
>>> identity_property_map is only for unsigned ints (it's that way for
>>> historical reasons).  Use typed_identity_property_map<entry_t> as
>>> prop_map_t and see if that fixes your problem.
>>>
>>> -- Jeremiah Willcock
>>>
>> Hi,
>> I've tried what you suggested and another error apperars:
>
> Could you please post the relevant part of the new code?  It appears
> that the storage indexing is messed up in the property map, and it
> could be that you need a different index map (if you're using
> boost::shared_ptr<CAStarNode> as the index type in the property map).
>
>> it seams that the operator[] has to be defined but I don't understand
>> why is it required if it is already specified to use a vector<entry_t>
>> as storage type
>>
>> Any suggestion?
>> Is there a full example on how to use mutable_queue with non-basic
>> types??
>
> I doubt it -- mutable_queue is mostly used internally.  If we end up
> working one out together I can put it in, though.
>
> -- Jeremiah Willcock
>   
Here's the code for the class I want to used the mutable_queue:

class CAStarNode;
#include <boost/shared_ptr.hpp>
typedef boost::shared_ptr<CAStarNode> CAStarNodePtr;

class CAStarNode
{

public:
    CAStarNode(const CVector2& point, const long int& g, const long int&
h):point_(point),g_(g),h_(h),f_(g + h)    {parent_.reset();};
    CAStarNode(const CVector2& point, const long int& g, const long int&
h, CAStarNodePtr parent)
    :point_(point),g_(g),h_(h),f_(g + h), parent_(parent){};
    CAStarNode(const CAStarNode&
n):point_(n.point_),g_(n.g_),h_(n.h_),f_(n.g_ + n.h_),parent_(n.parent_){};

    void operator=(const CAStarNode& n)   {  // copy suff }
    bool operator<(const CAStarNode& n) const {return (f_ < n.f_);}
    bool operator>(const CAStarNode& n) const {return (f_ > n.f_);}

    CVector2 getPoint() const {return point_;};
    long int getF() const {return f_;};
    long int getH() const {return h_;};
    long int getG() const {return g_;};
    void setG(const long int g)
    {
        g_ = g;
        f_ = g_ + h_;
    };
    CAStarNodePtr getParent() const {return parent_;};
    void setParent(CAStarNodePtr parent) {parent_ = parent;};

private:
    CVector2 point_;
    long int g_, h_, f_;    
    CAStarNodePtr parent_;        // Backpointer

};

// a criterion to sort a priority_queue /mutable_queue
namespace astarnode
{
    struct SGreater : std::binary_function<CAStarNodePtr&,
CAStarNodePtr&, bool>
    {
        bool operator()(const CAStarNodePtr& n1, const CAStarNodePtr&
n2) const
        {
            return (*n1 > *n2);
        }
    };
}

typedef CAStarNodePtr entry_t;
typedef vector<entry_t> storage_t;
typedef astarnode::SGreater comp_t;
typedef boost::typed_identity_property_map<entry_t> prop_map_t;
typedef boost::mutable_queue<entry_t, storage_t, comp_t, prop_map_t>
queue_t;

Then in the cpp file:

queue_t open(100, comp_t(), prop_map_t());

CAStarNodePtr currNode;
currNode.reset(new CAStarNode(start_, 0, value));
open.push(currNode);

Basically, I use the mutable_queue to keep sorted a vector of pointers
of CAStarNode's.
The project only fails to build when using the mutable_queue methods,
not the definition itself.

Thank you,

Emili
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