A way to filter range by indices, to get min_element from filtered indices only?

Question

In comments to this question is-there-a-way-to-iterate-over-at-most-n-elements-using-range-based-for-loop there was additional question - is this possible to have "index view" on a container, i.e. to have subrange with some indexes filtered out.

Additionally I encountered a problem to find minimum value from a range with some indexes filtered out.

I.e. is it possible to replace such code as below with std and/or boost algorithms, filters - to make it more readable and maintainable:

template <typename Range, typename IndexPredicate>
auto findMin(const Range& range, IndexPredicate ipred) 
     -> boost::optional<typename Range::value_type>
{
    bool found = false;
    typename Range::value_type minValue{};
    for (std::size_t i = 0; i < range.size(); ++i)
    {
        if (not ipred(i))
            continue;
        if (not found)
        {
            minValue = range[i];
            found = true;
        }
        else if (minValue > range[i])
        {
            minValue = range[i];
        }
    }
    if (found)
    {
        return minValue;
    }
    else
    {
        return boost::none;
    }
}

Just to be used like this:

#include <iostream>
#include <vector>

int main() {
    std::vector<float> ff = {1.2,-1.2,2.3,-2.3};
    auto onlyEvenIndex = [](auto i){ return (i&1) == 0;};

    auto minValue = findMin(ff, onlyEvenIndex);
    std::cout << *minValue << std::endl;
}

Answer 1

Using the recently Standard range-v3 proposal:

#include <range/v3/all.hpp>
#include <iostream>
#include <vector>

int main() 
{
    std::vector<float> rng = {1.2,-1.2,2.3,-2.3};

    auto even_indices = 
        ranges::view::iota(0ul, rng.size()) | 
        ranges::view::filter([](auto i) { return !(i & 1); })
    ;
    auto min_ind = *ranges::min_element(
        even_indices, [&rng](auto L, auto R) { 
        return rng[L] < rng[R]; 
    });
    std::cout << rng[min_ind];
}

Live Example. Note that the syntax is roughly similar to Boost.Range, but fully revamped to take advantage of C++14 (generalized lambdas, auto return type deduction etc.)