Re: pure function
- To: mathgroup at smc.vnet.net
- Subject: [mg87363] Re: [mg87332] pure function
- From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
- Date: Tue, 8 Apr 2008 07:17:00 -0400 (EDT)
- References: <200804080934.FAA11916@smc.vnet.net>
On 8 Apr 2008, at 18:34, haitomi wrote:
> Hello All,
>
> I need help with two pure functions
>
> 1) Li[Ranlist,x] that return a list of x element selected at random
> from Ranlist. (Is there any way to gennerate random from Ranlist? I
> have RanList=Range[-100,100])
>
> 2) the function 4Sumf[x] is computing the sum of 4 squares of x. If
> I have x=1, this function will gennerate 1^2+0^2+0^2+0^2, if x=4
> then 2^2+0^2+0^2+0^2, if x=7 2^2+1^2+1^2+1^2
>
> Is anyone out there have any idea?
> Thanks All,
> Tomi
>
With Mathematica 6:
1) Selections with replacement or without replacement?
With replacement:
RandomChoice[Range[-100, 100], 6]
{58, 13, -51, 66, -40, -69}
without replacement:
RandomSample[Range[-100, 100], 6]
{-38, 67, 83, 79, 3, -3}
(2).
PowersRepresentations[1, 4, 2]
{{0, 0, 0, 1}}
PowersRepresentations[7, 4, 2]
{{1, 1, 1, 2}}
All this has to be (and can be) done quite differently with earlier
versions of Mathematica but as you do not specify your version I
assume you have the latest.
Andrzej Kozlowski
- References:
- pure function
- From: haitomi <tpnycity@yahoo.com>
- pure function