Re: need help
- To: mathgroup at smc.vnet.net
- Subject: [mg87330] Re: [mg87308] need help
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Tue, 8 Apr 2008 05:34:29 -0400 (EDT)
- Reply-to: hanlonr at cox.net
ri = RandomInteger[{-100, 100}, 10]
{-19,-96,85,-6,-60,-21,40,78,-4,-82}
ri[[RandomInteger[Length[ri]]]]
78
sumf[x_Integer] := FindInstance[
a^2 + b^2 + c^2 + d^2 == x, {a, b, c, d}, Integers][[1]]
sumf /@ {1, 4, 7}
{{a->0,b->0,c->1,d->0},{a->0,b->0,c->2,d->0},{a->1,b->1,c->2,d->1}}
Bob Hanlon
---- haitomi <tpnycity at yahoo.com> 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? For example 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 then 2^2+1^2+1^2+1^2
>
> Is anyone out there have any ideas?
> Thanks All,
> Tomi
>