[Boost-users] [accumulators] help/advise required: Need a container to hold accumulator_set

Subject: [Boost-users] [accumulators] help/advise required: Need a container to hold accumulator_set
From: dhruva (dhruva_at_[hidden])
Date: 2009-02-21 22:51:57

Hello,
 I am writing a wrapper class which gets data over time and has to compute a variety of statistics using boost::accumulators. The accumulator cannot be a variable on the stack (function local variable) as it will go out of scope after the function invocation. I will have to make it a member variable of a class. I will not know the type of calculations to requested at compile time. I therefore need a generic accumulator type as member and add the specific type at runtime.

In short, I need a container to hold accumulator_set objects. Different type of accumulator_set objects in the container will perform different calculations. The type of calculation I want to perform will be based on input at runtime.

pseudo code:

#define MEAN 1
#define MAX 2

class calc {
public:
  setmetric(int metricType) {
    accumulator_set<double, features<> > *pacc;
    if (1 == metricType) {
        pacc = new accumulator_set<double, features <tag::mean> >;
    } else if(2 == metricType) {
        pacc = new accumulator_set<double, features <tag::max> >;
    }
    m_Vacc.push_back(pacc);
  }

  compute(double input) {
      // I will iterate over the vector, get the accumulator_set objects
      // acc_obj(input) followed by extract
  }

private:
  std::vector <accumulator_set<double, features<> > *> m_Vacc;
};

If features could be added at runtime, I probably could have solved this problem. Other approach is to have an accumulator_set with all supported features (supported by my application) as dropable. Drop all the unnecessary features based on user input. By adding all supported types, I will get a complete accumulator_set class at compile time and having a container to hold it is straight forward.
 Any help or advise is really appreciated. I may have raised a lot of basic questions but I am a boost newbie and taking a plunge.

-dhruva



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