/// <summary> Transition function through the graph </summary>
/// <param name="data"> Current graph state to transition </param>
/// <param name="place"> New vertex to transition to </param>
/// <returns> Results of transition </returns>
public WorkData Step(WorkData data, string place)
{
// If data is not already at the place we want to transition it to
if (data.at != place)
{
WorkData next = new WorkData();
// Started at the same place
next.start = data.start;
// Now at the new place
next.at = place;
// Apply the rate
next.rate = data.rate * this[data.at][place];
// Score the node based on gain per trades
next.score = (next.rate - 1.0) / data.path.Count;
// Copy all elements from the previous path into the new one
next.path = new List <string>(data.path);
// Then add the place it is at now
next.path.Add(place);
// Return built node
return(next);
}
// Already there? Return what we were given
return(data);
}
/// <summary> Entry point </summary>
/// <param name="args"> Command line args</param>
static void Main(string[] args)
{
// Read text from file
string text = File.ReadAllText(SourceFileDirectory() + "/stuff.dat");
// Split into lines
string[] lines = text.Split('\n');
// Create data structures
Graph graph = new Graph();
Queue <WorkData> queue = new Queue <WorkData>();
List <WorkData> profitable = new List <WorkData>();
// Loop over lines in file
foreach (string line in lines)
{
// Split each line, and remove empty strings
string[] parts = line.Split(' ', '\t').Where(it => (it != "")).ToArray();
// Skip lines that are not exactly 3 long
if (parts.Length != 3)
{
continue;
}
// Extract data from line: [ from, to, rate ]
string from = parts[0];
string to = parts[1];
double rate;
// Skip lines that don't have a number in 3rd element
if (!double.TryParse(parts[2], out rate))
{
continue;
}
// Add new verticies if they don't already exist
if (!graph.ContainsKey(from))
{
graph[from] = new Dictionary <string, double>();
}
if (!graph.ContainsKey(to))
{
graph[to] = new Dictionary <string, double>();
}
// Set transition rate into graph
graph[from][to] = rate;
graph[to][from] = 1.0 / rate;
}
// Loop over key/value pairs in graph
foreach (var pair in graph)
{
// Create a new work data that starts at each vertex,
WorkData data = new WorkData();
data.start = pair.Key;
data.at = pair.Key;
data.rate = 1.0;
data.score = 0.0;
data.path = new List <string>();
data.path.Add(pair.Key);
// and add it to our queue
queue.Enqueue(data);
}
Console.WriteLine("Ready. Running.");
// Time how long it takes
DateTime start = DateTime.UtcNow;
// While queue has stuff in it...
while (queue.Count > 0)
{
// Get front thing in queue
WorkData data = queue.Dequeue();
// Score this data to see how good it is
WorkData compare = graph.Step(data, data.start);
// Loop over graph:
foreach (var pair in graph)
{
// If we haven't been to that vertex yet
if (!data.path.Contains(pair.Key))
{
// Take transition to that location
WorkData next = graph.Step(data, pair.Key);
// Score the new data to see how good it is
WorkData final = graph.Step(next, data.start);
// See if it is profitable, then add it to the list of profitable trades
if (final.rate > 1)
{
profitable.Add(final);
}
// Ignore anywhere we lose money, even if it's still profitable
if (final.rate >= compare.rate)
{
queue.Enqueue(next);
}
}
}
}
// Finished! Take the time
DateTime end = DateTime.UtcNow;
TimeSpan diff = end - start;
// Sort our data in Ascending order
profitable.Sort((a, b) => (a.rate - b.rate) < 0 ? -1 : 1);
// Effecient output building (lots of text to append, avoid using += )
StringBuilder output = new StringBuilder();
// loop over all profitable paths
foreach (var profit in profitable)
{
// Console.WriteLine(profit.ShortString());
output.Append(profit.ShortString());
output.Append('\n');
}
Console.WriteLine("\n\nFinished in " + diff.TotalMilliseconds + "ms");
output.Append("\n\nFinished in " + diff.TotalMilliseconds + "ms");
// Sort our data in Decending order
profitable.Sort((a, b) => (a.rate - b.rate) > 0 ? -1 : 1);
Console.WriteLine("\n\nBest Overall Arbitrage: \n" + profitable[0]);
output.Append("\n\nBest Overall Arbitrage: \n" + profitable[0]);
// Sort our data in Decending order by scores instead:
profitable.Sort((a, b) => (a.score - b.score) > 0 ? -1 : 1);
Console.WriteLine("\n\nMost Efficient Arbitrage: \n" + profitable[0]);
output.Append("\n\nMost Efficient Arbitrage: \n" + profitable[0]);
// Dump output to file
File.WriteAllText(SourceFileDirectory() + "/outputcs.txt", output.ToString());
// Pause console, Don't need this unless running in VS2017
// Console.WriteLine("\nPress Enter to continue...");
// Console.Read();
}