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PhoenixXL

[solved] Information about SRandom()

15 posts in this topic

#1 ·  Posted (edited)

Hello Everyone

What does it mean by a SEED

Indeed upon using the Function SRandom the result of Random subsequently is always Constant

Can anyone tell me the significance of the function SRandom

Thanks in advance :)

Edited by PhoenixXL

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I didn't know it myself, but I found that it's the initializer of the random function. If you set the current time in the seed, the random will be based on this seed.

Br, FireFox.


 

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#3 ·  Posted (edited)

Thanks Firefox for the Link

But i have already tried that link

My question is what is the Significance of the Function

because it sets the subsequent Random calls a Constant

Local $rand

$rand = Random()
ConsoleWrite($rand&@CR) ;This is Random

SRandom(0)
$rand = Random()
ConsoleWrite($rand&@CR) ;Always constant i.e. 0.548813502304256
Edited by PhoenixXL

My code:

PredictText: Predict Text of an Edit Control Like Scite. Remote Gmail: Execute your Scripts through Gmail. StringRegExp:Share and learn RegExp.

Run As System: A command line wrapper around PSEXEC.exe to execute your apps scripts as System (LSA). Database: An easier approach for _SQ_LITE beginners.

MathsEx: A UDF for Fractions and LCM, GCF/HCF. FloatingText: An UDF for make your text floating. Clipboard Extendor: A clipboard monitoring tool. 

Custom ScrollBar: Scroll Bar made with GDI+, user can use bitmaps instead. RestrictEdit_SRE: Restrict text in an Edit Control through a Regular Expression.

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But i have already tried that link

OK sorry.

Yes that's weird... I'm waiting for a dev answer too ;)


 

OS : Win XP SP2 (32 bits) / Win 7 SP1 (64 bits) / Win 8 (64 bits) | Autoit version: latest stable / beta.
Hardware : Intel(R) Core(TM) i5-2400 CPU @ 3.10Ghz / 8 GiB RAM DDR3.

My UDFs : Skype UDF | TrayIconEx UDF | GUI Panel UDF | Excel XML UDF | Is_Pressed_UDF

My Projects : YouTube Multi-downloader | FTP Easy-UP | Lock'n | WinKill | AVICapture | Skype TM | Tap Maker | ShellNew | Scriptner | Const Replacer | FT_Pocket | Chrome theme maker

My Examples : Capture toolIP Camera | Crosshair | Draw Captured Region | Picture Screensaver | Jscreenfix | Drivetemp | Picture viewer

My Snippets : Basic TCP | Systray_GetIconIndex | Intercept End task | Winpcap various | Advanced HotKeySet | Transparent Edit control

 

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#5 ·  Posted (edited)

I don't see the point myself either, perhaps it's just an Artifact from the golden olden days.

SRandom(@hour / (@min + 1) + @sec) or something

I imagine AutoIt seeds internally.

Edited by JohnOne

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The internal seed is based on something more changing than seconds.

While 1
ConsoleWrite(Random() & @CrLf)
Sleep(0) ;JohnOne is the author, not me.
WEnd

 

OS : Win XP SP2 (32 bits) / Win 7 SP1 (64 bits) / Win 8 (64 bits) | Autoit version: latest stable / beta.
Hardware : Intel(R) Core(TM) i5-2400 CPU @ 3.10Ghz / 8 GiB RAM DDR3.

My UDFs : Skype UDF | TrayIconEx UDF | GUI Panel UDF | Excel XML UDF | Is_Pressed_UDF

My Projects : YouTube Multi-downloader | FTP Easy-UP | Lock'n | WinKill | AVICapture | Skype TM | Tap Maker | ShellNew | Scriptner | Const Replacer | FT_Pocket | Chrome theme maker

My Examples : Capture toolIP Camera | Crosshair | Draw Captured Region | Picture Screensaver | Jscreenfix | Drivetemp | Picture viewer

My Snippets : Basic TCP | Systray_GetIconIndex | Intercept End task | Winpcap various | Advanced HotKeySet | Transparent Edit control

 

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#7 ·  Posted (edited)

The internal seed is based on something more changing than seconds.

While 1
ConsoleWrite(Random() & @CrLf)
Sleep(0) ;JohnOne is the author, not me.
WEnd

Serously do not run that at it is

HotKeySet("{ESC}","_Exit")

Local $ScriptTimer = TimerInit()
Local $SleepTime = 0
SRandom(12)

While 1
    If TimerDiff($ScriptTimer) > 200 Then Exit ; exit after 0.2 seconds, else you will find yourself with a runaway console
    Sleep($SleepTime)
    ConsoleWrite(Random() & @LF)
WEnd

Func _Exit()
    Exit
EndFunc
Edited by JohnOne

AutoIt Absolute Beginners    Require a serial    Pause Script    Video Tutorials by Morthawt   ipify 

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It's pseudorandom i.e. maths. The generator is the Mersenne Twister.

The seed is the initial start value (x). With x = 0 the outcome is always the same obviously. Same goes for any other 'hardcoded' seed, it will always produce the same sequence of numbers. When using a changing value like @MSEC or something like that as a seed, such predictable patterns are avoided.

You only need to seed once, not everytime prior to calling Random()!


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Serously do not run that at it is

Computer not enough powerful ? :D

 

OS : Win XP SP2 (32 bits) / Win 7 SP1 (64 bits) / Win 8 (64 bits) | Autoit version: latest stable / beta.
Hardware : Intel(R) Core(TM) i5-2400 CPU @ 3.10Ghz / 8 GiB RAM DDR3.

My UDFs : Skype UDF | TrayIconEx UDF | GUI Panel UDF | Excel XML UDF | Is_Pressed_UDF

My Projects : YouTube Multi-downloader | FTP Easy-UP | Lock'n | WinKill | AVICapture | Skype TM | Tap Maker | ShellNew | Scriptner | Const Replacer | FT_Pocket | Chrome theme maker

My Examples : Capture toolIP Camera | Crosshair | Draw Captured Region | Picture Screensaver | Jscreenfix | Drivetemp | Picture viewer

My Snippets : Basic TCP | Systray_GetIconIndex | Intercept End task | Winpcap various | Advanced HotKeySet | Transparent Edit control

 

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Computer not enough powerful ? :D

lol probably not to be honest.

But I've been caught by something similar before

Even if you exit the script, the console still finishes all its writes

and it went on for about five minutes before I had to kill the process.

:)


AutoIt Absolute Beginners    Require a serial    Pause Script    Video Tutorials by Morthawt   ipify 

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You should only use SRandom() to initialize the Random() when you need to be able to produce the same sequence of numbers every time you run the script. An example of this might be for testing code where you need a random set of inputs, but need to use the same set of inputs for each test run after a code change, in order that the test conditions are the same.


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Even if you exit the script, the console still finishes all its writes

That's right, but you can normally close scite without any problem.

 

OS : Win XP SP2 (32 bits) / Win 7 SP1 (64 bits) / Win 8 (64 bits) | Autoit version: latest stable / beta.
Hardware : Intel(R) Core(TM) i5-2400 CPU @ 3.10Ghz / 8 GiB RAM DDR3.

My UDFs : Skype UDF | TrayIconEx UDF | GUI Panel UDF | Excel XML UDF | Is_Pressed_UDF

My Projects : YouTube Multi-downloader | FTP Easy-UP | Lock'n | WinKill | AVICapture | Skype TM | Tap Maker | ShellNew | Scriptner | Const Replacer | FT_Pocket | Chrome theme maker

My Examples : Capture toolIP Camera | Crosshair | Draw Captured Region | Picture Screensaver | Jscreenfix | Drivetemp | Picture viewer

My Snippets : Basic TCP | Systray_GetIconIndex | Intercept End task | Winpcap various | Advanced HotKeySet | Transparent Edit control

 

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You should only use SRandom() to initialize the Random() when you need to be able to produce the same sequence of numbers every time you run the script. An example of this might be for testing code where you need a random set of inputs, but need to use the same set of inputs for each test run after a code change, in order that the test conditions are the same.

I'd have to disagree with this as a general rule, maybe as a good idea for testing but certainly not the only reason to use it. If you're creating a random sequence and want to make sure that you can change the sequence when needed, you'd use a different seed otherwise you're going to keep getting the same sets of numbers. I came up with a latin square generator script that after a certain point you almost had to use a different seed to have it complete at all.

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Independant of the programming language, SRandom or Seed or whatever it's called is mainly used to ascertain a repeatable sequence of pseudo-random numbers across runs or across computers.


This wonderful site allows debugging and testing regular expressions (many flavors available). An absolute must have in your bookmarks.
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PCRE v8.33 regexp documentation latest available release and currently implemented in AutoIt beta.

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SQLite Expert (freeware Personal Edition or payware Pro version) is a very useful SQLite database manager.
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#15 ·  Posted (edited)

Independant of the programming language, SRandom or Seed or whatever it's called is mainly used to ascertain a repeatable sequence of pseudo-random numbers across runs or across computers.

Thanks to everyone

The Topic seems to be SOLVED now

Edited by PhoenixXL

My code:

PredictText: Predict Text of an Edit Control Like Scite. Remote Gmail: Execute your Scripts through Gmail. StringRegExp:Share and learn RegExp.

Run As System: A command line wrapper around PSEXEC.exe to execute your apps scripts as System (LSA). Database: An easier approach for _SQ_LITE beginners.

MathsEx: A UDF for Fractions and LCM, GCF/HCF. FloatingText: An UDF for make your text floating. Clipboard Extendor: A clipboard monitoring tool. 

Custom ScrollBar: Scroll Bar made with GDI+, user can use bitmaps instead. RestrictEdit_SRE: Restrict text in an Edit Control through a Regular Expression.

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