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cintaskep

Random function is creating the same numbers in 2 seperate instances of compiled script

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I am using AutoIt to generate 2 random numbers that act as unique seed numbers for an external program.  Even though I have compiled the script into an exe, running 2 instances of the exe simultaneously somehow means that the random numbers generated are exactly the same.  Can anyone shed some light as to why this is happening?

This is the log output of the 2 instances for each exe, showing: $DataFile, Random($Seed1), Random($Seed2)

 

Instance 1:

F:Garbage_SquidGarbageSquid1-1
0x74719660
0x81142742
F:Garbage_SquidGarbageSquid1-2
0x06222057
0x78780455
F:Garbage_SquidGarbageSquid1-3
0x35456052
0x27343546
F:Garbage_SquidGarbageSquid1-4
0x10657744
0x32951169

 

Instance 2:

G:Garbage_SquidGarbageSquid1-1
0x74719660
0x81142742
G:Garbage_SquidGarbageSquid1-2
0x06222057
0x78780455
G:Garbage_SquidGarbageSquid1-3
0x35456052
0x27343546
G:Garbage_SquidGarbageSquid1-4
0x10657744
0x32951169

etc.

 

I can get around this issue by using a unique identifier and scrambling the random number but I'm so curious as to why the random function is behaving this way!

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cintaskep,

Welcome to the AutoIt forum. :)

My initial thought is that you might be using the same seed - do you have SRandom in the code somewhere? :huh:

But it would certainly help if you posted the code you are using to create the random numbers - see here how to do it. :)

M23

 


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Marquee ----------- Scrolling tickertape GUIs
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Hi Melba, thanks for the welcome :)

I'm just using the Random function to create the variables that are then passed to an external program to do all sort of fun things.  The variables are set like this:

$Seed1_Random = Random(1, 88888888, 1)
$Seed2_Random = Random(1, 88888888, 1)

This issue is that the same numbers are generated when running the exe twice (at the same time)

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IIRC there has been a discussion some time ago about "how random is random". Unfortunately I can't find it at the moment.

Will post as soon as I'm successfull.


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cintaskep,

i can certainly reproduce your results - very interesting. :huh2:

I am afraid we will have to wait for jchd or another maths guru to come and explain why this happens - far beyond my very rusty maths skills. ;)

However, adding SRandom(@MSEC) and compiling separate instances gave entirely different sequences as I would have expected - even when the 2 were started quasi-simultaneously (one Running the other).  So that might be a solution for the immediate problem. ;)

M23


Any of my own code posted anywhere on the forum is available for use by others without any restriction of any kind._______My UDFs:

Spoiler

ArrayMultiColSort ---- Sort arrays on multiple columns
ChooseFileFolder ---- Single and multiple selections from specified path treeview listing
Date_Time_Convert -- Easily convert date/time formats, including the language used
ExtMsgBox --------- A highly customisable replacement for MsgBox
GUIExtender -------- Extend and retract multiple sections within a GUI
GUIFrame ---------- Subdivide GUIs into many adjustable frames
GUIListViewEx ------- Insert, delete, move, drag, sort, edit and colour ListView items
GUITreeViewEx ------ Check/clear parent and child checkboxes in a TreeView
Marquee ----------- Scrolling tickertape GUIs
NoFocusLines ------- Remove the dotted focus lines from buttons, sliders, radios and checkboxes
Notify ------------- Small notifications on the edge of the display
Scrollbars ----------Automatically sized scrollbars with a single command
StringSize ---------- Automatically size controls to fit text
Toast -------------- Small GUIs which pop out of the notification area

 

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Thanks Melba,

I've added in a Random(@MSEC) and multiplied that into the Random($Seed) to give a truly random number :)

I will be checking back to see what the guru's have to say about the earlier issue.

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#7 ·  Posted (edited)

cintaskep,
 

I've added in a Random(@MSEC) and multiplied that into the Random($Seed) to give a truly random number

I am not sure about that approach - the output from Random is as random as you can get so I cannot see why multiplying it again will make it even more so.  What I meant was more like this:

SRandom(@MSEC)

For $i = 1 To 10

    $Seed1_Random = Random(1, 88888888, 1)
    $Seed2_Random = Random(1, 88888888, 1)

Next

Now you start the Mesenne function using a random seed value (well, 0-999 anyway) and I do not get the same sequence from the 2 instances when run.  ;)

M23

Edited by Melba23
Typo

Any of my own code posted anywhere on the forum is available for use by others without any restriction of any kind._______My UDFs:

Spoiler

ArrayMultiColSort ---- Sort arrays on multiple columns
ChooseFileFolder ---- Single and multiple selections from specified path treeview listing
Date_Time_Convert -- Easily convert date/time formats, including the language used
ExtMsgBox --------- A highly customisable replacement for MsgBox
GUIExtender -------- Extend and retract multiple sections within a GUI
GUIFrame ---------- Subdivide GUIs into many adjustable frames
GUIListViewEx ------- Insert, delete, move, drag, sort, edit and colour ListView items
GUITreeViewEx ------ Check/clear parent and child checkboxes in a TreeView
Marquee ----------- Scrolling tickertape GUIs
NoFocusLines ------- Remove the dotted focus lines from buttons, sliders, radios and checkboxes
Notify ------------- Small notifications on the edge of the display
Scrollbars ----------Automatically sized scrollbars with a single command
StringSize ---------- Automatically size controls to fit text
Toast -------------- Small GUIs which pop out of the notification area

 

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#8 ·  Posted (edited)

PRNG (pseudo-random number generators) work by returning successive values from a very long to obscenely long sequences of numbers which are close to impossible to predict. The classical issue is the start point that the first run of Rand() will choose: it has to be itself strongly pseudo-random and that is one of the most vulnerable target Eve (the eyedropper) will aim to.

Unlike /dev/random from Unices (e.g. Linux) and AFAIK Windows doesn't have a cryptographically strong random seed primitive (or I don't know it, or it's hidden somewhere).

EDIT: above BS proven wrong, see later post.

Rand() in AutoIt is a very good PRNG and is fairly difficult to break in the general case: it's very hard to predict what Rand() will return next after it has been invoked once.

But --and that is a big butt if you allow me to state it that way-- the problem is, just as you experienced, that Rand() initializes itself to something related to time with high granularity. Using sRand() with a compound of processID and msec and something "hard enough to predict and duplicate" will alleviate the issue, but still be vulnerable to attack by a tech-savvy opponent.

The issue shouldn't surprise anyone: it's obviously hard to produce a reasonably random token from a machine relying on fully deterministic behavior. That's why hardware random sources using trully random physical processes in specific hardware are used in serious cryptographic applications.

I also remind that this point has been pointed out on this forum some time ago.

Edited by jchd

This wonderful site allows debugging and testing regular expressions (many flavors available). An absolute must have in your bookmarks.
Another excellent RegExp tutorial. Don't forget downloading your copy of up-to-date pcretest.exe and pcregrep.exe here
RegExp tutorial: enough to get started
PCRE v8.33 regexp documentation latest available release and currently implemented in AutoIt beta.

SQLitespeed is another feature-rich premier SQLite manager (includes import/export). Well worth a try.
SQLite Expert (freeware Personal Edition or payware Pro version) is a very useful SQLite database manager.
An excellent eBook covering almost every aspect of SQLite3: a must-read for anyone doing serious work.
SQL tutorial (covers "generic" SQL, but most of it applies to SQLite as well)
A work-in-progress SQLite3 tutorial. Don't miss other LxyzTHW pages!
SQLite official website with full documentation (may be newer than the SQLite library that comes standard with AutoIt)

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What jchd said, I learnt from Yashied to add SRandom(@AutoItPID) to the top of the script.


_AdapterConnections()_AlwaysRun()_AppMon()_AppMonEx()_BinaryBin()_CheckMsgBox()_CmdLineRaw()_ContextMenu()_ConvertLHWebColor()/_ConvertSHWebColor()_DesktopDimensions()_DisplayPassword()_DotNet_Load()/_DotNet_Unload()_Fibonacci()_FileCompare()_FileCompareContents()_FileNameByHandle()_FilePrefix/SRE()_FindInFile()_GetBackgroundColor()/_SetBackgroundColor()_GetConrolID()_GetCtrlClass()_GetDirectoryFormat()_GetDriveMediaType()_GetFilename()/_GetFilenameExt()_GetHardwareID()_GetIP()_GetIP_Country()_GetOSLanguage()_GetSavedSource()_GetStringSize()_GetSystemPaths()_GetURLImage()_GIFImage()_GoogleWeather()_GUICtrlCreateGroup()_GUICtrlListBox_CreateArray()_GUICtrlListView_CreateArray()_GUICtrlListView_SaveCSV()_GUICtrlListView_SaveHTML()_GUICtrlListView_SaveTxt()_GUICtrlListView_SaveXML()_GUICtrlMenu_Recent()_GUICtrlMenu_SetItemImage()_GUICtrlTreeView_CreateArray()_GUIDisable()_GUIImageList_SetIconFromHandle()_GUIRegisterMsg()_GUISetIcon()_Icon_Clear()/_Icon_Set()_IdleTime()_InetGet()_InetGetGUI()_InetGetProgress()_IPDetails()_IsFileOlder()_IsGUID()_IsHex()_IsPalindrome()_IsRegKey()_IsStringRegExp()_IsSystemDrive()_IsUPX()_IsValidType()_IsWebColor()_Language()_Log()_MicrosoftInternetConnectivity()_MSDNDataType()_PathFull/GetRelative/Split()_PathSplitEx()_PrintFromArray()_ProgressSetMarquee()_ReDim()_RockPaperScissors()/_RockPaperScissorsLizardSpock()_ScrollingCredits_SelfDelete()_SelfRename()_SelfUpdate()_SendTo()_ShellAll()_ShellFile()_ShellFolder()_SingletonHWID()_SingletonPID()_Startup()_StringCompact()_StringIsValid()_StringRegExpMetaCharacters()_StringReplaceWholeWord()_StringStripChars()_Temperature()_TrialPeriod()_UKToUSDate()/_USToUKDate()_WinAPI_Create_CTL_CODE()_WinAPI_CreateGUID()_WMIDateStringToDate()/_DateToWMIDateString()Au3 script parsingAutoIt SearchAutoIt3 PortableAutoIt3WrapperToPragmaAutoItWinGetTitle()/AutoItWinSetTitle()CodingDirToHTML5FileInstallrFileReadLastChars()GeoIP databaseGUI - Only Close ButtonGUI ExamplesGUICtrlDeleteImage()GUICtrlGetBkColor()GUICtrlGetStyle()GUIEventsGUIGetBkColor()Int_Parse() & Int_TryParse()IsISBN()LockFile()Mapping CtrlIDsOOP in AutoItParseHeadersToSciTE()PasswordValidPasteBinPosts Per DayPreExpandProtect GlobalsQueue()Resource UpdateResourcesExSciTE JumpSettings INISHELLHOOKShunting-YardSignature CreatorStack()Stopwatch()StringAddLF()/StringStripLF()StringEOLToCRLF()VSCROLLWM_COPYDATAMore Examples...

Updated: 04/09/2015

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OK I play guilty Windows has it for a long time even if its early security was not on par with expectations: http://en.wikipedia.org/wiki/CryptGenRandom

That would be a good default for SRandom().


This wonderful site allows debugging and testing regular expressions (many flavors available). An absolute must have in your bookmarks.
Another excellent RegExp tutorial. Don't forget downloading your copy of up-to-date pcretest.exe and pcregrep.exe here
RegExp tutorial: enough to get started
PCRE v8.33 regexp documentation latest available release and currently implemented in AutoIt beta.

SQLitespeed is another feature-rich premier SQLite manager (includes import/export). Well worth a try.
SQLite Expert (freeware Personal Edition or payware Pro version) is a very useful SQLite database manager.
An excellent eBook covering almost every aspect of SQLite3: a must-read for anyone doing serious work.
SQL tutorial (covers "generic" SQL, but most of it applies to SQLite as well)
A work-in-progress SQLite3 tutorial. Don't miss other LxyzTHW pages!
SQLite official website with full documentation (may be newer than the SQLite library that comes standard with AutoIt)

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You just reminded me >> #2263


_AdapterConnections()_AlwaysRun()_AppMon()_AppMonEx()_BinaryBin()_CheckMsgBox()_CmdLineRaw()_ContextMenu()_ConvertLHWebColor()/_ConvertSHWebColor()_DesktopDimensions()_DisplayPassword()_DotNet_Load()/_DotNet_Unload()_Fibonacci()_FileCompare()_FileCompareContents()_FileNameByHandle()_FilePrefix/SRE()_FindInFile()_GetBackgroundColor()/_SetBackgroundColor()_GetConrolID()_GetCtrlClass()_GetDirectoryFormat()_GetDriveMediaType()_GetFilename()/_GetFilenameExt()_GetHardwareID()_GetIP()_GetIP_Country()_GetOSLanguage()_GetSavedSource()_GetStringSize()_GetSystemPaths()_GetURLImage()_GIFImage()_GoogleWeather()_GUICtrlCreateGroup()_GUICtrlListBox_CreateArray()_GUICtrlListView_CreateArray()_GUICtrlListView_SaveCSV()_GUICtrlListView_SaveHTML()_GUICtrlListView_SaveTxt()_GUICtrlListView_SaveXML()_GUICtrlMenu_Recent()_GUICtrlMenu_SetItemImage()_GUICtrlTreeView_CreateArray()_GUIDisable()_GUIImageList_SetIconFromHandle()_GUIRegisterMsg()_GUISetIcon()_Icon_Clear()/_Icon_Set()_IdleTime()_InetGet()_InetGetGUI()_InetGetProgress()_IPDetails()_IsFileOlder()_IsGUID()_IsHex()_IsPalindrome()_IsRegKey()_IsStringRegExp()_IsSystemDrive()_IsUPX()_IsValidType()_IsWebColor()_Language()_Log()_MicrosoftInternetConnectivity()_MSDNDataType()_PathFull/GetRelative/Split()_PathSplitEx()_PrintFromArray()_ProgressSetMarquee()_ReDim()_RockPaperScissors()/_RockPaperScissorsLizardSpock()_ScrollingCredits_SelfDelete()_SelfRename()_SelfUpdate()_SendTo()_ShellAll()_ShellFile()_ShellFolder()_SingletonHWID()_SingletonPID()_Startup()_StringCompact()_StringIsValid()_StringRegExpMetaCharacters()_StringReplaceWholeWord()_StringStripChars()_Temperature()_TrialPeriod()_UKToUSDate()/_USToUKDate()_WinAPI_Create_CTL_CODE()_WinAPI_CreateGUID()_WMIDateStringToDate()/_DateToWMIDateString()Au3 script parsingAutoIt SearchAutoIt3 PortableAutoIt3WrapperToPragmaAutoItWinGetTitle()/AutoItWinSetTitle()CodingDirToHTML5FileInstallrFileReadLastChars()GeoIP databaseGUI - Only Close ButtonGUI ExamplesGUICtrlDeleteImage()GUICtrlGetBkColor()GUICtrlGetStyle()GUIEventsGUIGetBkColor()Int_Parse() & Int_TryParse()IsISBN()LockFile()Mapping CtrlIDsOOP in AutoItParseHeadersToSciTE()PasswordValidPasteBinPosts Per DayPreExpandProtect GlobalsQueue()Resource UpdateResourcesExSciTE JumpSettings INISHELLHOOKShunting-YardSignature CreatorStack()Stopwatch()StringAddLF()/StringStripLF()StringEOLToCRLF()VSCROLLWM_COPYDATAMore Examples...

Updated: 04/09/2015

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Just to put another point of view, having the ability to output the same sequence of pseudo random numbers can be very useful when testing and bug fixing. The AutoIt implementation of rand() and srand() seem to me to behave exactly the same as their C/C++ namesakes.


"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the universe trying to build bigger and better idiots. So far, the universe is winning."- Rick Cook

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SRandom($SomeConstant) can always be used for repetitive duplicate tests independant of environment just as in C and friends like you rightly say.


This wonderful site allows debugging and testing regular expressions (many flavors available). An absolute must have in your bookmarks.
Another excellent RegExp tutorial. Don't forget downloading your copy of up-to-date pcretest.exe and pcregrep.exe here
RegExp tutorial: enough to get started
PCRE v8.33 regexp documentation latest available release and currently implemented in AutoIt beta.

SQLitespeed is another feature-rich premier SQLite manager (includes import/export). Well worth a try.
SQLite Expert (freeware Personal Edition or payware Pro version) is a very useful SQLite database manager.
An excellent eBook covering almost every aspect of SQLite3: a must-read for anyone doing serious work.
SQL tutorial (covers "generic" SQL, but most of it applies to SQLite as well)
A work-in-progress SQLite3 tutorial. Don't miss other LxyzTHW pages!
SQLite official website with full documentation (may be newer than the SQLite library that comes standard with AutoIt)

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