[R] Odp: ^ operator

[carol white]

but with complex, I get complex numbers for the first and last elements:

> (as.complex(tmp))^(1/3)
[1] 0.01969170+0.03410703i 0.03478442+0.00000000i 0.03285672+0.00000000i
[4] 0.08950802+0.00000000i 0.05848363+0.10129661i

whereas for the first element, we get the followings.

Moreover, 
> -6.108576e-05^(1/3)
>  [1] -0.03938341
and
> -(6.108576e-05^(1/3))
[1] -0.03938341
and
 -((6.108576e-05)^(1/3))
[1] -0.03938341

give the same results.

so using () doesn't preserve any thing

--- On Mon, 11/16/09, Petr PIKAL <petr.pikal at precheza.cz> wrote:

> From: Petr PIKAL <petr.pikal at precheza.cz>
> Subject: Odp: [R] ^ operator
> To: "carol white" <wht_crl at yahoo.com>
> Cc: r-help at stat.math.ethz.ch
> Date: Monday, November 16, 2009, 3:40 AM
> Hi
> 
> AFAIK, this is issue of the preference of operators. 
> 
> r-help-bounces at r-project.org
> napsal dne 16.11.2009 11:24:59:
> 
> > Hi,
> > I want to apply ^ operator to a vector but it is
> applied to some of the 
> > elements correctly and to some others, it generates
> NaN. Why is it not 
> able to
> > calculate -6.108576e-05^(1/3) even though it exists?
> > 
> > 
> >  tmp
> > [1] -6.108576e-05  4.208762e-05 
> 3.547092e-05  7.171101e-04 
> -1.600269e-03
> > > tmp^(1/3)
> > [1]        NaN 0.03478442
> 0.03285672 0.08950802        NaN
> 
> This computes (-a)^(1/3) which is not possible in real
> numbers. You have 
> to use as.complex(tmp)^(1/3) to get a result.
> 
> > > -6.108576e-05^(1/3)
> > [1] -0.03938341
> 
> this is actually
> -(6.108576e-05^(1/3))
> 
> Regards
> Petr
> 
> 
> > 
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