English 中文(简体)
Implementation Detail for Graph Analysis Algorithms
原标题:

Let s say I have a graph with "heavy" nodes, that is each node is an object that is already carrying a lot of data. I want to do a graph transformation that requires me to calculate a special property for each node. This property only needs to be remembered temporarily to apply the transformation. How can I store this property efficiently?

Adding a special_property field to each node seems like a waste as I only need to remember it for a short time. Another possibility is to create a "shadow" graph, which is a graph that has the exact same connections as the original one and only storing the special_property though this seems unwieldy.

What is a generally acceptable way to tackle this problem?

最佳回答

Each node should have a small integer identifier. Use it as an index to store the properties in a temporary array. Besides O(1) access time, an array also has great data locality for the processor cache.

问题回答

The "heavy" objects should not be the actual nodes in the graph. Each node in the graph should have a pointer to the "heavy" object it represents and whatever other attributes you need when operating on the graph.

Check out Boost library





相关问题
How to add/merge several Big O s into one

If I have an algorithm which is comprised of (let s say) three sub-algorithms, all with different O() characteristics, e.g.: algorithm A: O(n) algorithm B: O(log(n)) algorithm C: O(n log(n)) How do ...

Grokking Timsort

There s a (relatively) new sort on the block called Timsort. It s been used as Python s list.sort, and is now going to be the new Array.sort in Java 7. There s some documentation and a tiny Wikipedia ...

Manually implementing high performance algorithms in .NET

As a learning experience I recently tried implementing Quicksort with 3 way partitioning in C#. Apart from needing to add an extra range check on the left/right variables before the recursive call, ...

Print possible strings created from a Number

Given a 10 digit Telephone Number, we have to print all possible strings created from that. The mapping of the numbers is the one as exactly on a phone s keypad. i.e. for 1,0-> No Letter for 2->...

Enumerating All Minimal Directed Cycles Of A Directed Graph

I have a directed graph and my problem is to enumerate all the minimal (cycles that cannot be constructed as the union of other cycles) directed cycles of this graph. This is different from what the ...

Quick padding of a string in Delphi

I was trying to speed up a certain routine in an application, and my profiler, AQTime, identified one method in particular as a bottleneck. The method has been with us for years, and is part of a "...

热门标签