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22 seconds to sort 100,000 integers?? Are you running this on an Atari 800? That's horrible performance for a Quicksort.
I've got a Mergesort implementation in my toolbox that'll sort 10,000,000 integers in less than 12 seconds - single threaded.
Windows will not automatically rework your code to run in on multiple cores. No O/S will do that. YOU have to do that my rewriting your code. I'd concentrate on reworking your implementation to get better performance on a single thread first before you start to worry about how you're going to multithread this. Multithreading a poor implementation doesn't get you anything but more threads running poorly.
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Hi,
This quick sort couldn't be so bad. Ok, it is not an optimized QuickSort.
I think it depends also on the input data you provide. I have used other sorting algorithms with these data set and I get comparative results.
But still I don't have any answer here.
modified 18-Jan-13 11:12am.
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George Nistor wrote: This quick sort couldn't be so bad
Oh yeah?? Quick sort normally has about 95% of the performance of Merge sort, given a proper implementation. Try recoding to use arrays only and skill all the stack collection garbage.
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I think the stack operations are slowing your algorithm. Quicksort only needs a simple array.
The generic operations that are "array-like" will reallocate a NEW array and copy all the elements to this array when the old array isn't long enough to hold a new element. This gives O(n^2) performance, which is slow. (Quicksort should be O(n log n)).
Using multiple threads to speed Quicksort is a good idea because the partitioning lets the threads work independently, without requiring synchronization. You just have to make sure your basic operations aren't wasting time.
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thanks Alan, I have realized after I looked on the
Stack<t>(Int32) Constructor.
I fixed the problem and now I was able to run it 2 times faster, in 9-10 seconds for the same dataset.
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That's still horrible performance for Quick sort.
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Considering a Quick sort should run about 1,500 times faster than what you're now reporting, you've got major problems. 10,000 integers should take less than 0.01 seconds on todays hardware - single threaded.
Try reading Scalable Multithreaded Programming with Thread Pools[^] for a threaded Quick sort example.
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I use as test a vector with 100 000 ints. It is ordered in Descending order.
(another problem I have choosed partition element at one end, result in a small partition on a Descending order data set  )
I have tried an optimized Insertion and it sorts it in 20s. c++
I think I test the worst case scenario which is N2 for both inserion and quicksort.
In average cases it works super fast, in less than a second;
I got like you with 10 mils of ints around 3 sec.
int[] V;
const int sizeV = 10000000;
Random rnd = new Random();
for (int i = 0; i < sizeV; ++i)
V[i] = rnd.Next(0, 9999999);
modified 18-Jan-13 16:37pm.
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OK, Solved.
It works really fast even without a selection first.
(I can sort 50 millions of ints in 15 seconds)
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Hello all,
I have 2 Datasets. I've already asked how to join 2 DataSets and didn't get any answers that helped me. So I feel the easiest way to associate them now is to create a dictionary(s) for DataSet2.
The 2 different DataSets have only 1 field in common, CompanyName. So enter dicitonary.
DataSet 2 contains only 16 total records (Company). Each record (Company) has 7 rows:
<company>
<companyname>Company1
<name>Carrington Mortgage Services, LLC
<maddress1>1610 E. Saint Andrew Place
<maddress2>B150
<mcity>Santa Ana
<mstate>CA
<mzip>92705
So when CompanyName matches, return value from Dictionary.
Do i need to create 16 Dicitonary entires with Key and Value? Do i create 1 Dictionary with variables populating on some kind of for loop? I was told that i could create my own class to store the information I need or simply set the dataset record as the value. No idea what any of those things mean. 
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If you do that (and I'm not saying you should or shouldn't) you probably ought to at least define a class to hold each entry and then have Dictionary<string,MyClass>
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Do you mean like this?
public class Companies
{
public static String Company1 { get { return "Company1";}}
public static String Company1City { get { return "Company1City";}}
public static String Company1State { get { return "Company1State";}}
public static String Company2 { get { return "Company2";}}
public static String Company2City { get { return "Company2City";}}
public static String Company2State { get { return "Company2State";}}
}
or like this?
Public Class Company1
{
}
Public Class Company2
{
}
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Maybe more like the latter, but do you really need two classes? If so, possibly add a third (abstract) one, and an Interface! Oooh! And an equality operator! And and and...
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No idea how to achieve all of that. Sorry. Beginner here.
But your enthusiasm is, nice.
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class Company
{
public string Name { get; set; }
public List<Loan> Loans { get; }
public Company()
{
this.Loans = new List<Loan>();
}
}
class Loan
{
public string CompanyName { get; set; }
}
static class Main()
{
Dictionary<string, Company> companies = new Dictionary<string, Company>();
foreach (DataRow row in companyDataSet.Tables["Company"].Rows)
{
Company current = new Company();
current.Name = row.CompanyName;
}
foreach (DataRow row in loanDataSet.Tables["Loan"].Rows)
{
Loan currentLoan = new Loan();
currentLoan.CompanyName = row.CompanyName;
companies[currentLoan.CompanyName].Loans.Add(currentLoan);
}
}
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Huor,
Thank so much for your time. This is very helpful and at least sends me in the right direction!
It seems like most experienced programmers are too jaded to offer help here. Like giving a handout to a poor person that hasn't helped themselves.
Like I'm just looking for a handout because I'm too stupid to google or use the "search" features. "Oh please Mr programming constultant, help me for free, please, my family is dying from starvation and and...my dog has fleas...I need more code"
"Begone peasant!! I have no time for new coders! I'm solving much higher and more important recursion problems and pointer issues! Why don't you use the search feature."
Bah!
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I linked some file to my project (console project). I have two questions:
1) Is there a way to edit the link, without doing it manually? (is there the link path written somewhere in the project?)
2) Can I commute the link in a local copy of the linked file quickly?
Thanks
Germoz
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I'm unsure exactly what you are asking, but maybe I can shed some light for you anyway.
The project file is just XML and a regular included source file may look like this:
<Compile Include="CompileException.cs" />
A linked (Add as link) file may look like this:
<Compile Include="..\PIEBALD\Types\XmlNode.cs">
<Link>XmlNode.cs</Link>
</Compile>
Because it's XML, you can edit it, but you should make a backup and be careful.
I use linked files a lot.
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You get perfectly the point! Very helpful
Thanks a lot
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hi guys , im using zeromq dll for making server/client program . the program works fine . but i want to run the setup of the program that i have made , in other computer with(win xp). it w'll throw an error
System.DllNotFoundExpection:Unable to load Dll 'libzmq':The specified procedure could not be found.(Exception from HRESULT:0x8007007F)
at ZeroMQ.Interop.zmq_init(Int32_threads)
at ZeroMQ.ZmqSocket..Ctor(int32 type,Nullable 1 context)
at ZeroMQ.ZmqDealerSocket..ctor()
at ChatClient.Client.Main(string[] args) in c:\my Development\ZeroMq\ZeroMQ_ChatTest\ChatClient\Client.cs:Line 13
but i have already attach the libzmq in the folder . so can any one tell me what's the problem ?
and sth more , it'll not throw an error if i run the setup on win 7 .
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Are you sure you have installed/available all the dependencies in the other computer. like .Netframework,runtime libraries etc.The error looks like failed to load the libzmq.dll because of an error inside the dll. is there any other dll referred inside the libzmq.dll also copied in the destination PC?
Jibesh V P
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wohooo , i solve it 
it was need a xml file that linked to libzmq
ty ty
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Nice. good to hear that.
Jibesh V P
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