Re: [boost] [ boost ] [ Trie ]

2015-03-05 2:55 GMT+03:00 Cosmin Boaca :

Hello,

I have modified the directory strucure. I think it's ok right now.

...

Another significant and hard task: trie_node structure looks too heavy: there are too many member variables. Try to simplify trie_node and value_list_node structures. Think of a possible optimizations of the trie_node structure for trie_set|trie_map|trie_multiset|trie_multimap. For example all the sets do not require values, so pointers to value list nodes can be removed from trie_set in that case.

I have thought of this task too. I will share with you some ideas in order to get some feedback about them.

1. Value = void specialization for trie_node which would remove pointers to value_list_head/tail, self_value_count.

+1

2. Another specialization or something like this would be ok for trie_map also. The map_node should only contain a member value_type value. value_list_head/tail, self_value_count should be removed in this case to but I don't know how to specialize the template (for which key, value) type.

+1 How about adding aditional template parameter to map node. Something like template class map_node;

3. Considering 2, trie_multiset could be easily implemented in terms of trie_map, maybe using private inheritance. The int would keep track of the frequency of the key prefix.

+1

4. value_count could be completely removed but this would greatly reduce the performance of count_prefix function. In my opinion this shouldn't be removed.

This is discussable. Let's solve this some time later.

I don't know too much about pred_node, next_node, and the child_iter_of_parrent. I need to take some more time to look at those things to see if any of them could be removed. I see that pred_node and next_node are used in trie_iterator and child_iter_of_parrent is used to maintain the values of pred_node and next_node. However, I don't know which would be the tradeofs of the removal for each of them.

Let's eat an elephant part by part. There's more than enough tasks right now, even without *_node and child_iter_of_parrent.

Looking forward to your feedback about the ideas above.

Good progress! Trie library becoming better and better. -- Best regards, Antony Polukhin