Dear all,
The accumulators library is a very nice way to get a set of statistics for a stream of numbers, doubles, say.
Now let’s suppose I’m receiving a stream of boost::optional<double>s – e.g. let’s suppose I’m receiving simulation results and some simulations fail.
It would be neat if I could somehow write and “adaptor accumulator” that took this stream of optionals and then, if they are not empty, pass them to an underlying accumulator.
In rough terms:
template struct accumulator_adaptor
{
template<typename Args> void operator()( Args const& args)
{
Sample const& s = args[sample];
if( s )
{
m_underlying_accumulator( *s ) ; //doesn’t compile UnderlyingAccumulator expects an Args, not a Sample
}
}
private:
UnderlyingAccumulator m_underlying_accumulator;
};
(we might also define another accumulator that just counts the number of “bad” samples.
Then by adding an appropriate feature adaptor, one could write something like
accumulator_set< boost::optional<double> , tag::accumulator_adaptor< mean > , tag::bad_samples_count >
For the data 1.0,2.0,boost::optional<double>(),4.0
This would return a mean of 7/3 and a bad_samples_count of 1.
Is it possible for me to implement such an adaptor that would work for an arbitrary underlying accumulator?
Thanks for your interest,
Pete
