Re: [Boost-users] Statistical Accumulator

Subject: Re: [Boost-users] Statistical Accumulator
From: Kraus Philipp (philipp.kraus_at_[hidden])
Date: 2010-07-07 12:09:03

Am 07.07.2010 um 17:52 schrieb Eric Niebler:

> On 7/7/2010 11:00 AM, Kraus Philipp wrote:
>>
>> Am 07.07.2010 um 14:00 schrieb Eric Niebler:
>>
>>> On 7/6/2010 4:31 PM, Kraus Philipp wrote:
>>>> Hi,
>>>>
>>>> I try to calulate the covariance from some data.
>>>>
>>>> http://www.boost.org/doc/libs/1_43_0/doc/html/accumulators/user_s_guide.html#accumulators.user_s_guide.the_statistical_accumulators_library.covariance
>>>>
>>>>
>>>> I don't understand the call "acc call". I would like to rebuild  
>>>> the cov
>>>> command form Matlab for matrix data
>>>> (http://www.mathworks.com/access/helpdesk/help/techdoc/ref/ 
>>>> cov.html).
>>>> If this is correct, when I give as the first argument of command  
>>>> data
>>>> from the first line and second as the  data of the first column  
>>>> to the
>>>> first value to calculate the new matrix?
>>>>
>>>> I try try compile the excample, but I get a compiler error on the
>>>> "acc::tag::covariate1":
>>>>
>>>>   acc::accumulator_set<double,  
>>>> acc::stats<acc::tag::covariance<double,
>>>> acc::tag::covariate1> > > xx;
>>>>
>>>>   xx(1., acc::tag::covariate1 = 2.);
>>>>   xx(1., acc::tag::covariate1 = 4.);
>>>>   xx(2., acc::tag::covariate1 = 3.);
>>>>   xx(6., acc::tag::covariate1 = 1.);
>>>>
>>>>   std::cout << acc::covariance(xx) << std::endl;
>>>>
>>>> The error text: "expected primary-expression befor = token".  
>>>> Sorry, it's
>>>> a little bit late, so I don't see my mistake
>>>
>>> It's impossible to say from just the little code fragment you've
>>> included here. Have you #include
>>> <boost/accumulators/statistics/covariance.hpp>?
>>>
>>> Please include a complete example that demonstrates the problem next
>>> time.
>>
>> Yes, I have had take the example form the Boost page:
>> http://boost-sandbox.sourceforge.net/libs/accumulators/doc/html/accumulators/user_s_guide/the_statistical_accumulators_library.html#accumulators.user_s_guide.the_statistical_accumulators_library.covariance
> --------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> FYI, that's not where Boost's documentation lives. For the most recent
> docs, see:
>
> http://www.boost.org/doc/libs/1_43_0/doc/html/accumulators/user_s_guide.html#accumulators.user_s_guide.the_statistical_accumulators_library.covariance
>
>> Mean and other statistical function works, but only the covariance  
>> doesn't
>
> I think you need to add:
>
>    #include <boost/accumulators/statistics/variates/covariate.hpp>
>
> The following program compiles for me:
>
>    #include <boost/accumulators/accumulators.hpp>
>    #include <boost/accumulators/statistics/covariance.hpp>
>    #include <boost/accumulators/statistics/variates/covariate.hpp>
>    #include <boost/assert.hpp>
>
>    namespace acc = boost::accumulators;
>
>    int main()
>    {
>        acc::accumulator_set<double,
> acc::features<acc::tag::covariance<double, acc::tag::covariate1> > >  
> acc;
>        acc(1., acc::covariate1 = 2.);
>        acc(1., acc::covariate1 = 4.);
>        acc(2., acc::covariate1 = 3.);
>        acc(6., acc::covariate1 = 1.);
>        BOOST_ASSERT(acc::covariance(acc) == -1.75);
>    }
>
> I'll add this information to the docs.

Thanks works fine. I don't include the variates/covariate.hpp