Hi i am Creating Big List in C# the Values are Calulated by local Variable and then i use them in list it Work but takes around 30 sec to complete just to create the final list i want to use Parallel as i see currently my program only use one thread

thnx any help Simplified Code Below

   decimal USDT  = Rs;
   decimal Pound = Rs;
   decimal Ruble= Rs;

 List<Author> authors = new List<Author>

//the Value are get by calling some other function 

//How To Speed up This part below

authors.Add(new Author { Name = "1", Price = value(1) , PriceinRs =USDT  * value(1)});
authors.Add(new Author { Name = "2", Price = Value(2) , PriceinRs =Ruble * value(2)});
authors.Add(new Author { Name = "3", Price = Value(3) , PriceinRs =Pound * value(3)});
...
//Total Around 2000 Other Authors

CodePudding user response：

Would it not be faster to define PriceinRs in the Author class as PriceinRs => Price * Currency and define a Currency in the Author class, instead of assigning the value? Assuming USDT and Rubble and Pound are currencies.

CodePudding user response：

Here you have a full example with 4 ways but...

Be aware, parallelism is not always the better option especially with sets with lots of data and simple operations, like your example.

You can play with this example and change the length of data in Enumerable.Range(1, xxx) and see times results:

• Example with 1000000*5 authors:

WAY 1, for 853
WAY 2, linq 448
WAY 3, parallel for each 1407
WAY 4, parallel with Partitioner 407

• Example with 1000000*1 authors:

WAY 1, for 190
WAY 2, linq 90
WAY 3, parallel for each 209
WAY 4, parallel with Partitioner 304

• Example with 1000000*10 authors:

WAY 1, for 962
WAY 2, linq 1747
WAY 3, parallel for each 1137
WAY 4, parallel with Partitioner 2690

In your case, i recommend you for or linq options.

CODE

// Set exchange rate
double usdt = 1.5667;
double btc = 21340.6532;

// Get authors with other funcion
var authors = Enumerable.Range(1, 1000000*10).Select(x=> new Author
{
    Name = "Author "   x.ToString(),
    usdtCoins = x*1000,
    btcCoins = x
}).ToList();


// WAY 1, for
var authorsCalculated = new List<Author>();
var timer = Stopwatch.StartNew();

foreach (var author in authors)
{
    authorsCalculated.Add(new Author
    {
        Name = author.Name,
        usdtCoins = author.usdtCoins,
        btcCoins = author.btcCoins,
        usdtMoney = author.usdtCoins * usdt,
        btcMoney = author.btcCoins * btc
    });
}

timer.Stop();
Console.WriteLine("WAY 1, for " timer.ElapsedMilliseconds);

// WAY 2, linq
authorsCalculated = new List<Author>();
timer.Restart();

authorsCalculated = authors.Select(x=> new Author {
    Name = x.Name,
    usdtCoins = x.usdtCoins,
    btcCoins = x.btcCoins,
    usdtMoney = x.usdtCoins * usdt,
    btcMoney = x.btcCoins * btc
}).ToList();

timer.Stop();
Console.WriteLine("WAY 2, linq "   timer.ElapsedMilliseconds);

// WAY 3, parallel for each
authorsCalculated = new List<Author>();
var authorsCalculated_ConcurrentBag = new ConcurrentBag<Author>();
timer.Restart();

Parallel.ForEach(authors, author =>
{
    // Each parallel add one item on concurrent bag = safe list
    authorsCalculated_ConcurrentBag.Add(new Author
    {
        Name = author.Name,
        usdtCoins = author.usdtCoins,
        btcCoins = author.btcCoins,
        usdtMoney = author.usdtCoins * usdt,
        btcMoney = author.btcCoins * btc
    });
});

authorsCalculated = authorsCalculated_ConcurrentBag.ToList();

timer.Stop();
Console.WriteLine("WAY 3, parallel for each "   timer.ElapsedMilliseconds);


// WAY 4, parallel with Partitioner
// https://stackoverflow.com/questions/4031820/when-to-use-partitioner-class
authorsCalculated = new List<Author>();
var authorsCalculated_ConcurrentBag2 = new ConcurrentBag<List<Author>>();
timer.Restart();

Parallel.ForEach(Partitioner.Create(0, authors.Count()), range => {
    var innerList = new List<Author>();
    for (var index = range.Item1; index < range.Item2; index  )
    {
        innerList.Add(new Author
        {
            Name = authors[index].Name,
            usdtCoins = authors[index].usdtCoins,
            btcCoins = authors[index].btcCoins,
            usdtMoney = authors[index].usdtCoins * usdt,
            btcMoney = authors[index].btcCoins * btc
        });
    }
    authorsCalculated_ConcurrentBag2.Add(innerList);
});

foreach (var l in authorsCalculated_ConcurrentBag2)
{
    authorsCalculated.AddRange(l);
}

timer.Stop();

Console.WriteLine("WAY 4, parallel with Partitioner "   timer.ElapsedMilliseconds);