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Re: issue generating table of random numbers

  • To: mathgroup at smc.vnet.net
  • Subject: [mg81925] Re: issue generating table of random numbers
  • From: Mark Fisher <particlefilter at gmail.com>
  • Date: Sat, 6 Oct 2007 04:51:15 -0400 (EDT)
  • References: <fe4v33$1kh$1@smc.vnet.net>

On Oct 5, 5:10 am, John Molina <johnjmol... at gmail.com> wrote:
> Hi, I'm running Mathematica 6 on OsX (10.4) and have been experiencing difficulties generating a table of random numbers (a table of random matrices actually).
> matrix = Table[RandomChoice[{-1, 1}, {4, 4}], {250}]
> for a table size less than 250 it seems to work fine but for larger sizes mathematica is flattening out the lists:
> matrix[[i]] = {-1,1,1,-1}
> and not
>             = {{-1,1},{1,-1}}
> As far as I can tell this is only happening with the RandomChoice command (RandomInteger and RandomReal work fine). Does anyone know what is happening? is this a bug?
> thanks

Very spooky:

Table[Dimensions[Table[RandomChoice[{-1, 1}, {4, 4}], {i}]], {i, 249,
  250}]

This ways seems correct:

Table[Dimensions[RandomChoice[{-1, 1}, {i, 4, 4}]], {i, 249, 250}]

--Mark



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