Gennaro Prota:
I would recommend that you seriously show how to make simpler implementations. I'm sure that significant simplifications, that work as well as the more complicated implementation, would be accepted, if you are willing to provide enough of the simpler implementation. I'm also positive that you would be acknowledged for such work.[...] in many cases boost has implementations enormously more complicated than necessary.
Striking a good balance is very difficult. I would recommend that you seriously propose alternatives. I'm sure such proposals will be considered.To me instead simplicity is important as much as other aspects, and should be abandoned _only_ when it comes, for instance, at correctness' or completeness' cost.
Not that I know of. I've known the basic definitions concerning shift operators and unsigned integral types for a long time.I think you are missing something here, maybe the important fact that an integer type (unsigned long included) may have padding bits or the rules about shift operators.
The point was that the algorithm core does significantly fewer recursions. Sure, you can get bogged down in the details of the C++ language, if you want to. I was aware of the fact that the technique I used for calculating the initial shift count was not perfect when I sent my initial reply. The specifics of calculating the proper initial shift count is a minor detail of the overall algorithm.
Please reread the paragraph of my previous post that starts with: "In this case it is not necessary to know the exact number of value bits." If the initial shift count is chosen correctly, which can always be done, the recursion always terminates with the case log2<1,0>.Proof please?[...]
Are those specialization for the naïve algorithm?[...]adding specializations at "regular intervals", i.e.template <> struct log2<16> .. template <> struct log2<256> ... template <> struct log2<4096> ... In both cases the timings were practically the same[...]
In that case it is not very surprising that they do not significantly improve the efficiency of the algorithm. In order for such a set of specialization to be effective, you would need quite a few of them. For instance, to reduce the maximum time to half on 32-bit unsigned longs, you would need something like 2^15 or 2^16 specializations, which is not very practical.
Regards,
Vesa Karvonen
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