Random()

[Radiance]

Hi all,

sometimes when I'm generating two random numbers just after another using the Random() function, I'm getting the same values.

This happens far too often to be random.

Has anybody else experienced this? Is there any way to avoid it without adding a sleep between the two randoms?

[computergroove]

I havent experienced this but it is possible. Its maybe more likely that there is a coding error. You could make an if statement that says:

Global $LastRandom

While 1
    Local $Random = Random(0,10,1)
    If $LastRandom == $Random Then
    Do
        $Random = Random(0,10,1)
    Until $LastRandom <> $Random
        MsgBox(0,"Random Number",$Random)
    Else
    MsgBox(0,"Random Number",$Random)
    EndIf
    $LastRandom = $Random
WEnd

[czardas]

If you try to avoid the same number repeating, then you are avoiding the random chance that the same number will repeat. If you run Random(1, 10, 1) 1000 times, each number (1-10) will occur on average about 100 times - in any order.

Edited December 3, 2014 by czardas

[computergroove]

When I ran random I was getting the same number in a row around 1 in 10-15 tries. I didn't see the issue you are having. Can you provide some code?

[Yashied]

Try to use SRandom() at the beginning of your script:

 

SRandom(@AutoItPID)

[computergroove]

I made this with the help of a moderator to show the results of random:

expandcollapse popup

#include <GUIConstantsEx.au3>

Global $aLabel[11], $bStart = False

$hGUI = GUICreate("Form1", 157, 438, 336, 218)
GUICtrlCreateLabel("Random Number Count", 16, 16, 115, 17)
For $i = 1 To 10
    GUICtrlCreateLabel("1", 24, 152 + (24 * $i), 10, 17)
    $aLabel[$i] = GUICtrlCreateLabel(0, 64, 152 + (24 * $i), 30, 17)
Next
GUICtrlCreateLabel("Speed", 32, 120, 35, 17)
$cSpeed = GUICtrlCreateInput(100, 24, 136, 49, 21)
$cStart = GUICtrlCreateButton("Start", 24, 48, 89, 25)

$ButtonResetCount = GUICtrlCreateButton("Reset Count", 24, 80, 89, 25)
GUISetState(@SW_SHOW)

$nTimeStamp = TimerInit()

While 1
    Switch GUIGetMsg()
        Case $GUI_EVENT_CLOSE
            Exit
        Case $cStart
            Switch GUICtrlRead($cStart)
                Case "Start"
                    GUICtrlSetData($cStart, "Stop")
                    $bStart = True
                Case Else
                    GUICtrlSetData($cStart, "Start")
                    $bStart = False
            EndSwitch
        Case $ButtonResetCount
            ResetCount()
    EndSwitch

    If $bStart Then
        If TimerDiff($nTimeStamp) > GUICtrlRead($cSpeed) Then
            $iRandom = Random(1, 10, 1)
            GUICtrlSetData($aLabel[$iRandom], GUICtrlRead($aLabel[$iRandom]) + 1)
            $nTimeStamp = TimerInit()
        EndIf
    EndIf

WEnd

Func ResetCount()
    For $i = 1 To 10
        GUICtrlSetData($aLabel[$i], 0)
    Next
    $bStart = False
EndFunc   ;==>ResetCount

[Radiance]

If you try to avoid the same number repeating, then you are avoiding the random chance that the same number will repeat. If you run Random(1, 10, 1) 1000 times, each number (1-10) will occur on average about 100 times - in any order.

 

I am aware of this. Since the numbers I use are usually too big and I get this result pretty often it's hard to believe that it's still random.

Sorry. I forgot to add that I'm only having this issue when running more than one script on random.

Check this out:

This is just an example I did a minute ago.

I've got a server software launching other AutoIt scripts, using asynchronous communication between them.

They get identified by a longer number I'm rolling at random when the "child"script starts.

When two of them happen to get launched directly after anouther they get the same ID and I get really weird results.

 

Edit:

 

I made this with the help of a moderator to show the results of random

 

This is really awesome to look at.

Edited December 3, 2014 by Radiance

[Exit]

I made this with the help of a moderator to show the results of random:

YOU made nothing !!!

It is the original code of MELBA23

And you even copied the error in line 8:

 

GUICtrlCreateLabel(1, 24, 152 + (24 * $i), 10, 17)

should be

GUICtrlCreateLabel($i, 24, 152 + (24 * $i), 10, 17)

[computergroove]

Wow.... I made the idea, I made the original faulty code, I pursued the right answer. I ran it and it worked. I made it to share in this post and I even gave props to the moderator for helping. What's the big deal here? Rest assured Im not getting paid for my efforts nor am I hiding anything.

When you are running 2 of these back to back you are probably doing so withing the same second (This is a guess). Try adding sleep(1000) between those and see if the results are different. From what I have heard there is no real random in computer language. The program is probably taking the date and time and running it through an algorithm and displaying the results. If you change a variable it should change the output.

Edited December 3, 2014 by computergroove

[MikahS]

Wow.... I made the idea, I made the original faulty code, I pursued the right answer. I ran it and it worked. I made it to share in this post and I even gave props to the moderator for helping. What's the big deal here? Rest assured Im not getting paid for my efforts nor am I hiding anything.

When you are running 2 of these back to back you are probably doing so withing the same second (This is a guess). Try adding sleep(1000) between those and see if the results are different. From what I have heard there is no real random in computer language. The program is probably taking the date and time and running it through an algorithm and displaying the results. If you change a variable it should change the output.

 

A link to the topic would have been just fine.

Back on topic, is the goal to run more than one script using random at the same time?

[SmOke_N]

@Exit and @computergrove, play nice.

@Radiance, Yashield gave you what you needed in post #5, you need a seed basically.

<snip>, cute, I wrote out basically what SRandom said in the help file before I thought that it was probably explained there!.... Just see the helpfile lol

[czardas]

I forgot to add that I'm only having this issue when running more than one script on random.

 

Interesting discovery.

[Melba23]

Hi,

I knew this had been discussed before, but it took a while to find it.

M23

[Unc3nZureD]

As it had been said, use SRandom, so you can set a seed. Probably Autoit automatically uses time() function as a seed, which can cause such problems. If you choose a better Seed (like the previously mentioned PID) you can avoid it.