Random(): differences script vs compled exe

[Dana]

I'm finding some more weirdness in the Random function.

Do
    (some stuff)
    $randidx[$i] = Random(1, $array[0], 1) ; pick a random integer between 1 and $array[0] 
    (some more stuff)
    $i = $i + 1
Until $i = $desired + 1

If I run the script from SciTE, a get a different set of random numbers each time, as expected. However, if the script is compiled to an exe, I get the same set of numbers each time I run the exe.

Is this a bug? What is the Random function using as a seed if SRandom isn't used?

It doesn't seem to be too big a deal; adding:

SRandom(_Date_Time_GetTickCount())

just before the Do loop solves it even in the exe, but I'd like to know what's going on... and why the compiled executable should behave differently from the uncompiled script?

Edited February 4, 2011 by Dana

[Melba23]

Dana,

Just tried and I get random random numbers each time I run this script both in SciTE and compiled:

Global $aArray[10]

For $i = 0 To 9
    $aArray[$i] = Random(0, 1000, 1)
Next

MsgBox(0, "Result", $aArray[0] & @CRLF & _
                    $aArray[1] & @CRLF & _
                    $aArray[2] & @CRLF & _
                    $aArray[3] & @CRLF & _
                    $aArray[4] & @CRLF & _
                    $aArray[5] & @CRLF & _
                    $aArray[6] & @CRLF & _
                    $aArray[7] & @CRLF & _
                    $aArray[8] & @CRLF & _
                    $aArray[9])

I also use the Random function in my desktop MP3 player and it certainly does not repeat the same tracks each time I run it.

M23

[Dana]

I dunno why it should be different, but I consistent got the same set of "random" numbers each time I ran the exe version... that's why I was wondering what gets used as a seed if you don't use the SRandom function first.

Hmmm... if I compile it (your example) with obfuscator, it breaks and I get the same series every time. If I don't use obfuscation, it works as it should.

[MvGulik]

Your post is empty Edited February 9, 2011 by iEvKI3gv9Wrkd41u

[Melba23]

Dana,

Even when the script above is Obfuscated (/sf /sv /om /cs=0 /cn=0) I still get random random numbers.

M23

[willichan]

$randidx[$i] = Random(1, $array[0], 1) ; pick a random integer between 1 and $array[0]

Is $array[0] returning a value of 1 by any chance? If the Min and Max are the same number, Random returns a 0 and sets @error.

See this discussion -->

If that is your case, I posted a little function to "fix" it in that thread.

[Dana]

No, $array[0] is in the neighborhood of 5,000 or so.

Melba23, I'm using the default Obfuscator settings during compile.

Strange... at work I get the repeated results I described with the above example. At home, it works properly. Guess I'll have to wait until Monday to see what the difference may be.

Interestingly, I looked at the obfuscated au3 file and I see that obfuscator added the line:

SRandom(Number(StringRight(TimerInit(),4)))

even though SRandom isn't used in the original code.

[Dana]

Grrr... returning to the office this morning, both the obfuscated and unobfuscated compiled versions return a different random series each time, as it should.

Which makes me question: The obfuscated version adds the line with the SRandom function which isn't in my original script. (why?) That line uses TimerInit as input to SRandom. I know TimerInit "Returns a timestamp (in milliseconds)" according to the helpfile, but a time based on what? If the computer has been on for a long time (a week or two, as it was before I shut it down last Friday) would it "max out" and return the same value each time?

[jvanegmond]

Ofcourse, if you have a truly random dice and you throw it an infinite number of times, the probably of it rolling on the same number a hundred times in a row are approaching 100%. Maybe you were the lucky one.

In all the years I have used AutoIt I have never seen the timestamp "max out". That would also probably have been noticed, since it will lead to unexplained bugs in long-running scripts in a production environment and cause someone to do some serious debugging.

Perhaps you were facing an issue like this one:

While 1
    $time = TimerInit()
    ; Do all kinds of things
    ; Do all kinds of things
    ; Do all kinds of things
    ; Do all kinds of things
    ; Do all kinds of things
    ; Do all kinds of things
    ; Do all kinds of things
    ; Do all kinds of things
    ; Do all kinds of things
    $time = 5
    ; Do all kinds of things
    ; Do all kinds of things
    ; Do all kinds of things
    ; Do all kinds of things
    ; Do all kinds of things
    ; Do all kinds of things
    ; Do all kinds of things
    ; Do all kinds of things
    ; Do all kinds of things
    
    ; Oh how convenient, don't need to call timerinit again
    SRandom($time)
    ; Pure delicous rando~.. OH WWHAT!! *Makes thread*
    ConsoleWrite(Random(0, 10) & @CRLF)
WEnd

Edited February 8, 2011 by Manadar

[MvGulik]

Your post is empty Edited February 9, 2011 by iEvKI3gv9Wrkd41u

[Jos]

whatever

Why a post edit with a well know phrase but hidden?

Referring to anything happened recently?

[MvGulik]

Your post is empty Edited February 9, 2011 by iEvKI3gv9Wrkd41u

[Yashied]

Redirecting off topic item. -> ←

SRandom(@AutoItPID)

[Jos]

Redirecting off topic item. -> ←

Correct .....

[MvGulik]

Your post is empty Edited February 12, 2011 by iEvKI3gv9Wrkd41u