Using valarray instead of vector for Array type.

[kalwalt]

At the moment i declared all the members inside data_t class as vector's because they are Array's

webarkit-jsfeat-cpp/src/types/types.h

Line 13 in c02edb5

template <typename T> using Array = std::vector<T>;

But maybe we could try to use valarray instead of vector STL container, it has some advantages, for example it includes math functions (abs sin, cos..) and slicing yhe array that could be very useful. I will make some test, and will report here.

[kalwalt]

Converting the code to valarray, has some drawbacks, it lacks of vector functions like empty(), data(), assign(). Because the code now it use these functions, i need to understand if it possible to convert the code without these functions.

[kalwalt]

But we could implement a different matrix_t class based on valarray and then make a comparison with some tests.