Integer value Rotation problem - C / C++ / MFC Discussion Boards

Re: compile file exe

Emilio Garavaglia4-Aug-10 21:51

Emilio Garavaglia

4-Aug-10 21:51

Don't underestimate the italian to english Google translators. Big Grin | :-D

50% of Italian techincal text is made by inglish words, and 30% of italian neologism taken from english!

It is vice-versa that is a nightmare (when you got the translation even of what shouldn't)
I often have to back-traslate italian to english to understand what the italian text really means!

2 bugs found.
> recompile ...
65534 bugs found.
D'Oh! | :doh:

OpenMP outperforms ordinary loop even with 1 thread limitation

Chesnokov Yuriy4-Aug-10 3:20

Chesnokov Yuriy

4-Aug-10 3:20

I've run that code on 2 core cpu

...
for (i = 0; i < N * N; i++)        
    vec3[i] = vec1[i] * vec2[i];
...

#pragma omp parallel for
for (i = 0; i < N * N; i++)
    vec3[i] = vec1[i] * vec2[i];

...

Even if I run it by setting explicitly omp_set_num_threads(1) to use just one thread it runs about 1.66 times faster. Using 2 threads the speed up is 2 times.

I've checked with omp_get_thread_num() how many threads were running.

What is the reason for single thread OpenMP to outperform ordinary for loop?

Чесноков

Re: OpenMP outperforms ordinary loop even with 1 thread limitation

Ahmed Charfeddine4-Aug-10 6:03

Ahmed Charfeddine

4-Aug-10 6:03

Hi,

Well there many possibilities.
Even using the ordinary loop, you can get different perfromance results between writing :

for (i = 0; i < N * N; i++)        
    vec3[i] = vec1[i] * vec2[i];

and writing this :

for (i = 0; i < N * N; i+=2)        {
    vec3[i] = vec1[i] * vec2[i];
    vec3[i+1] = vec1[i+1] * vec2[i+1];
}

So one hypothesis would be that the OpenMP look implementation knows the better way how to do the transfer of data.

The number of 1.66 should tell something. No doubt !

Let me guess, 1.66 is 5/3

If the process involves the repetition of N tasks, with each task lasting T duration then the new gain is 3/5 T
meaning we got rid of 2/5

There is a constant task, and that is the multiplication. It woud be too coincidential to get that 66 number if not the constant part is about the ..
Emmm I will think about this in the bus.
Good day.
1.66 means means

Easy Profiler : Now open source !
http://www.codeproject.com/KB/cpp/easyprofiler.aspx

Re: OpenMP outperforms ordinary loop even with 1 thread limitation

C^hris L^osinger4-Aug-10 9:49

C^hris L^osinger

4-Aug-10 9:49

i suspect the OpenMP optimizer has compiled your loop to SSE instructions, and therefore, you're doing two or four (or eight?) of those multiplications at a time.

look at the assembly, to verify.

image processing toolkits | batch image processing

Re: OpenMP outperforms ordinary loop even with 1 thread limitation

Sauro Viti4-Aug-10 21:10

Sauro Viti

4-Aug-10 21:10

I made some tests on my computer and I had a look to the assembler code produced by the compiler: it seems that the non-parallelized version of the loop use the mul opcode (then using the FPU stack), and the parallelized version use the mulsd opcode (then using SSE2). In both cases only a single multiplication is performed at a time, but using the FPU stack requires too much work to move the operands from memory to the stack and then the result from the stack to memory.

I hope this could help! Big Grin | :-D

Cheers,
Sauro

Multiple bitmaps in single row of CListCtrl

tenwang4-Aug-10 2:19

tenwang

4-Aug-10 2:19

Hi,

I want the following view on the CListCtrl, report view.

|Column A|Column B|Column C|Column D|
|Bitmap1 | Bitmap2 | Bitmap3 | Text |

Bitmap images in the three columns, and a text in the third column.

I am so confused about how to implement it.

I tried with this Neat Stuff to Do in List Controls Using Custom Draw[^] sample using custom draw, but could display bitmap in 1st column only.

I would like the row height(=Height of bitmap) to be larger then the default row height.

Re: Multiple bitmaps in single row of CListCtrl

David Crow4-Aug-10 3:11

David Crow

4-Aug-10 3:11

Have you tried the SetItem() method?

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Integer value Rotation problem

rrthangavel4-Aug-10 1:55

rrthangavel

4-Aug-10 1:55

Hi All,
As we know integer has value limitation's(ex +_32767) depends upon bit range(ex 32 bit,16 bit).
i'm working with an integer variable which gets input from text box(designed as Activex control).

my condition is if the user enters the value in text box greater than 10 means it should show the error symbol otherwise correct symbol.

so the problem is if i enter the value 10 to 36767 means it shows alert symbol. if it is above 32767 means it shows correct symbol.
How can i solve this integer value Rotation Problem?

waiting for u Rose | [Rose]

Re: Integer value Rotation problem

CPallini4-Aug-10 2:15

CPallini

4-Aug-10 2:15

rrthangavel wrote:
As we know integer has value limitation's(ex +_32767) depends upon bit range(ex 32 bit,16 bit).

It is (usually) -32768..32767 for signed shorts.

rrthangavel wrote:
How can i solve this integer value Rotation Problem?

Do you mean wrap-around problem?
It depends on how much control you have on the input. For instance, if you can read the input string, then a length > 2 is an error condition.
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Re: Integer value Rotation problem

Luc Pattyn4-Aug-10 3:15

Luc Pattyn

4-Aug-10 3:15

00000000000000000000000000000000000000000000000000000000000000000001

Smile | :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] Nil Volentibus Arduum

Please use <PRE> tags for code snippets, they preserve indentation, and improve readability.

Re: Integer value Rotation problem

CPallini4-Aug-10 3:19

CPallini

4-Aug-10 3:19

That's simply silly and the user must be punished for... Big Grin | :-D

Re: Integer value Rotation problem

Cedric Moonen4-Aug-10 2:19

Cedric Moonen

4-Aug-10 2:19

Can't you simply use unsigned values ? Confused | :confused:

Cédric Moonen
Software developer

Charting control [v3.0]
OpenGL game tutorial in C++

Re: Integer value Rotation problem

SnowHow4-Aug-10 2:41

SnowHow

4-Aug-10 2:41

You are going to have to add an event handler for OnChange so that you check the input on edit.

Re: Integer value Rotation problem

rrthangavel4-Aug-10 3:43

rrthangavel

4-Aug-10 3:43

i got it thanks yaar.

DeleteFile Hook

gothic_coder4-Aug-10 1:01

gothic_coder

4-Aug-10 1:01

Hello All,

I need to intercept everytime user use delete,shift-delete or use DEL command from command promt, I need to know what API get called when we use DELETE, SHIFT+DELETE and DEL command, I'll be very much obliged if anyone can redirect me to how to intercept-Hook those calls..

Looking forward to see members reply, and i'm using VC 6.0 and WIN DDK 7.1.

Thanks all

Re: DeleteFile Hook

elchupathingy4-Aug-10 3:45

elchupathingy

4-Aug-10 3:45

What exactly are you working on that needs to intercept the function calls and that needs the DDK and are using VC 6.0? But, this is simple to implement if you know where to look.

There are quite a few articles on how to intercept/hook a function call, especially a windows one.

Re: DeleteFile Hook

gothic_coder4-Aug-10 20:33

gothic_coder

4-Aug-10 20:33

I need to intercept if anyone delete the file and verify if it's authorized user to perform the action..

elchupathingy wrote:
and that needs the DDK and are using VC 6.0?

What are other way to perform this apart of making driver?

elchupathingy wrote:
There are quite a few articles on how to intercept/hook a function call, especially a windows one.

That's what i need, I couldn't find or i would say i couldn't find right articles, Can you post some link?

Thanks for your reply..

Re: DeleteFile Hook

elchupathingy5-Aug-10 9:02

elchupathingy

5-Aug-10 9:02

[]

[]

Those should get you started.

Re: DeleteFile Hook

gothic_coder5-Aug-10 23:01

gothic_coder

5-Aug-10 23:01

Didn't get the point..

Re: DeleteFile Hook

elchupathingy6-Aug-10 4:38

elchupathingy

6-Aug-10 4:38

Oh wow...the links didn't go through, sorry about that.

http://www.codeproject.com/KB/system/hooksys.aspx

http://www.codeproject.com/KB/threads/completeinject.aspx

The two articles here. Also you only need to use something like Windows Detours, I personally like Detours 1.5, but the newer one can do more things, but 1.5 is easier to use personally.

How to add combo box items to TreeListControl.

Sakhalean3-Aug-10 21:37

Sakhalean

3-Aug-10 21:37

I want to add combo box items to the list control
How to add items to combobox
and where to add combo box items.

to the tree list control

Pls help me.

Re: How to add combo box items to TreeListControl.

Niklas L4-Aug-10 0:00

Niklas L

4-Aug-10 0:00

This feature is not supplied by the MFC classes directly, but have a look at XListCtrl - A custom-draw list control with subitem formatting[^]. This control will probably supply what you need.

If you're not using MFC, well then the sample is a good place to start anyway, implementing your own class.

Good luck.

home

Re: How to add combo box items to TreeListControl.

Sakhalean4-Aug-10 0:44

Sakhalean

4-Aug-10 0:44

i want to insert (strings to) combo box of the treelistcontrol
developed by TigerX

[]

Re: How to add combo box items to TreeListControl.

Iain Clarke, Warrior Programmer4-Aug-10 10:05

Iain Clarke, Warrior Programmer

4-Aug-10 10:05

Sakhalean wrote:
i want to insert (strings to) combo box of the treelistcontrol
developed by TigerX

Have you tried asking "tigerx" ?

Iain.

I am one of "those foreigners coming over here and stealing our jobs". Yay me!

Need application working for timer basis

Game-point3-Aug-10 20:29

Game-point

3-Aug-10 20:29

Hi All,

I create one sample win32 console application, which that application working for timer basis.

Example :
If the user gives the stared work is 1:00 AM and End Work is 3:30 AM and the current time is 1:30 AM then application will be in active till 3:30 AM. It automatically goes to idle state, if the system time crosses the end time that have been configured. The application will start again with in the timeframe on next day and so on.

how to achieve this application using threading

please share your valuable thoughts

Thanks n advance

Raju K

Failure is Success If we learn from it!!

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.