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Topic: Random numbers
Replies: 64   Last Post: Dec 24, 2007 1:04 PM

 Messages: [ Previous | Next ]
 quasi Posts: 12,067 Registered: 7/15/05
Re: Random numbers
Posted: Dec 21, 2007 9:52 AM

On 21 Dec 2007 16:41:26 +0200, Phil Carmody
<thefatphil_demunged@yahoo.co.uk> wrote:

>quasi <quasi@null.set> writes:
>> On 21 Dec 2007 16:20:58 +0200, Phil Carmody
>> <thefatphil_demunged@yahoo.co.uk> wrote:
>>

>> >quasi <quasi@null.set> writes:
>> >> On 21 Dec 2007 14:53:38 +0200, Phil Carmody
>> >> <thefatphil_demunged@yahoo.co.uk> wrote:
>> >>

>> >> >quasi <quasi@null.set> writes:
>> >> >> On 21 Dec 2007 14:33:08 +0200, Phil Carmody
>> >> >> <thefatphil_demunged@yahoo.co.uk> wrote:
>> >> >>

>> >> >> >John <iamachamp@gmail.com> writes:
>> >> >> >> Given a function that returns a random number between 1-5, write one
>> >> >> >> that returns a random number between 1-7 for the case when it should
>> >> >> >> be integer and for the case it can be real.

>> >> >> >
>> >> >> >int rand1to7i()
>> >> >> >{
>> >> >> > int r1=rand1to5i();
>> >> >> > if(r1==5) { r1+=rand1to5i()/2; }
>> >> >> > return r1;
>> >> >> >}

>> >> >>
>> >> >> Fatally flawed.

>> >> >
>> >> >Wrong. Care to back up your claim? Between you and me, I
>> >> >reckon you've not thought about my response enough.

>> >>
>> >> Yes, do a simulation, and then _you_ think about it.

>> >
>> >What do you think the simulation will prove, and why do you
>> >think that's important?
>> >

>> >> >> >double rand1to7d()
>> >> >> >{
>> >> >> > return rand1to5d()+(rand1to5d()-1)/2;
>> >> >> >}

>> >> >>
>> >> >> Inefficient -- uses 2 RNG calls, instead of 1.

>> >> >
>> >> >Wrong. If you stretch the numbers out, you'll leave gaps
>> >> >between them, these aren't actual reals, you did realise
>> >> >that, right? You *need* 2 calls to ensure that you leave
>> >> >no gaps.

>> >>
>> >> Forget gaps -- your method is biased!

>> >

>>

>
>So I saw. And laughed.

I think you're in the wrong field.

You should try politics.

quasi

Date Subject Author
12/21/07 Champ
12/21/07 quasi
12/21/07 quasi
12/21/07 Phil Carmody
12/21/07 quasi
12/21/07 quasi
12/21/07 Phil Carmody
12/21/07 quasi
12/21/07 Phil Carmody
12/21/07 Phil Carmody
12/21/07 quasi
12/21/07 quasi
12/21/07 Phil Carmody
12/21/07 quasi
12/21/07 Phil Carmody
12/21/07 Phil Carmody
12/21/07 quasi
12/21/07 Phil Carmody
12/21/07 quasi
12/21/07 Marshall
12/21/07 Phil Carmody
12/21/07 quasi
12/21/07 Phil Carmody
12/21/07 Marshall
12/21/07 briggs@encompasserve.org
12/21/07 William Elliot
12/21/07 quasi
12/22/07 William Elliot
12/21/07 Pubkeybreaker
12/21/07 b92057@yahoo.com
12/22/07 quasi
12/21/07 simple.popeye@gmail.com
12/21/07 simple.popeye@gmail.com
12/22/07 quasi
12/22/07 Gib Bogle
12/22/07 quasi
12/21/07 Marshall
12/22/07 simple.popeye@gmail.com
12/22/07 quasi
12/22/07 simple.popeye@gmail.com
12/22/07 quasi
12/22/07 quasi
12/22/07 quasi
12/22/07 simple.popeye@gmail.com
12/22/07 quasi
12/23/07 simple.popeye@gmail.com
12/23/07 simple.popeye@gmail.com
12/23/07 simple.popeye@gmail.com
12/23/07 simple.popeye@gmail.com
12/23/07 simple.popeye@gmail.com
12/22/07 simple.popeye@gmail.com
12/22/07 Herman Rubin
12/22/07 b92057@yahoo.com
12/22/07 quasi
12/23/07 b92057@yahoo.com
12/23/07 quasi
12/23/07 b92057@yahoo.com
12/24/07 quasi
12/24/07 quasi