Re: [boost] [Accumulators] Passing construction arguments to dependent statistics

From: Hugo Duncan (hugoduncan_at_[hidden])
Date: 2007-08-01 14:36:14

> The resulting argument pack is passed as the constructor parameter to
> all the accumulators in the set. Your accumulator can then extract the
> coefficients argument from the pack with "args[coefficients]".

Done this, but I want to pass an array of values to coefficients, ie it  
looks like, eg:

    array<double,5> coeffs={0.1,0.2,0.1};
    accumulator_set<... > acc( .., coefficients = coeffs, ...);

So far so good.

My filter depends on the delay buffer I have defined which has the  
cache_size constructor argument.  Since I am specifying the list of  
coefficients, I want the cache_size to be set to the number of elements in  
my coefficient list, with out having to specify it, ie without having to  
write:

    array<double,5> coeffs={0.1,0.2,0.1};
    accumulator_set<... > acc( .., coefficients = coeffs, cache_size=5...);

Not sure if this is possible through boost::Parameters (first time I have  
seen this used, BTW, I'm impressed), or if I need to have the filter  
access the delay post construction, or if it is just not possible.