Is RANDOM command broken? Topic is solved

[joefiesta]

The following should, I think, generate random number from 0 to 2**31-1. It seems not too. Is my code incorrect or is RANDOM broken?

Code: Select all

a := ""
tot := 0
iter := 100
max  := 21474893647
loop %iter%
  {
  random, b, 0, %max%
  a .= " "b
  tot += b
  }

msgbox % "iteratinons: " iter  "`nMax:`t" max "`tAverage:`t"  tot/iter "`n"a
exitapp        

[Odlanir]

You specified 21474893647 as the max number but doc says:

The largest number that can be generated, which can be negative, floating point, or an expression. If omitted, the largest number will be 2147483647 (which is also the largest allowed integer value -- but floating point numbers have no restrictions).

[swagfag]

random has an upper range of (2^31)-1. the number youre feeding to random exceeds this upper limit, overflows a bunch of times and what ends up happening is youre running random with (0, 57177)

[joefiesta]

yeah, thanks... I just noticed my typo (and extra 9 in the number).

[Odlanir]

@swagfag : Out of curiosity, how do you get the number 57177 ? Since I ran the Op code ( several time with 10.000.000 iterations ) and the max number for me is 57167.

[BoBo]

yeah, thanks... I just noticed my typo (and extra 9 in the number).

What gives me the idea that c&p is our friend

[jeeswg]

Here we go:

Code: Select all

q:: ;overflow
;21474893647 = 0x50000DF4F ;typo
;2147483647 = 0x7FFFFFFF ;correct number

VarSetCapacity(vData, 4, 0)
NumPut(21474893647, &vData, 0, "Int")
MsgBox, % NumGet(&vData, 0, "Int") ;57167

;not quite the right calculation:
MsgBox, % Mod(21474893647, 2147483647) ;57177

;possibly the right calculation (although would give an unsigned integer, not a signed integer):
MsgBox, % Mod(21474893647, (2147483647+1)*2) ;57167
return

[swagfag]

@swagfag : Out of curiosity, how do you get the number 57177 ? Since I ran the Op code ( several time with 10.000.000 iterations ) and the max number for me is 57167.

its a miscalculation on my part: i subtracted (2^31 - 1) a bunch of times, instead of just 2^31