square-root

Good day, A friend of mine is asking about transforming an integer square root function into a meta-function. Here is the original function: unsigned isqrt(unsigned value) { unsigned sq = 1, dlt = 3; while(sq<=value) { sq += dlt; dlt += 2; } return (dlt>>1) - 1; } I wrote a meta version using constexpr , but he said he can't use the new feature for some reason: constexpr std::size_t isqrt_impl (std::size_t sq, std::size_t dlt, std::size_t value){ return sq <= value ? isqrt_impl(sq+dlt, dlt+2, value) : (dlt >> 1) - 1; } constexpr std::size_t isqrt(std::size_t value){ return isqrt_impl(1, 3,

I'm trying to learn algorithms and coding stuff by scratch. I wrote a function that will find square roots of square numbers only, but I need to know how to improve its performance and possibly return square roots of non square numbers function squareroot(number) { var number; for (var i = number; i >= 1; i--) { if (i * i === number) { number = i; break; } } return number; } alert(squareroot(64)) Will return 8 Most importantly I need to know how to improve this performance. I don't really care about its limited functionality yet Here is a small improvement I can suggest. First - start

What is the difference between x**(1/2) , math.sqrt() and cmath.sqrt() ? Why does cmath.sqrt() get complex roots of a quadratic right alone? Should I use that for my square roots exclusively? What do they do in the background differently? If you look at the documentation for cmath and math respectively, you will find that: cmath "provides access to mathematical functions for complex numbers" math "functions cannot be used with complex numbers; use the functions of the same name from the cmath module if you require support for complex numbers." The (**) operator maps to the pow function, with

I have been trying to figure out how to programmatically find a square root of a number in Swift. I am looking for the simplest possible way to accomplish with as little code needed. I now this is probably fairly easy to accomplish, but can't figure out a way to do it. Any input or suggestions would be greatly appreciated. Thanks in advance Paul Buis In Swift 3, the FloatingPoint protocol appears to have a squareRoot() method. Both Float and Double conform to the FloatingPoint protocol. So: let x = 4.0 let y = x.squareRoot() is about as simple as it gets. The underlying generated code should

Notice For a solution in Erlang or C / C++ , go to Trial 4 below. Wikipedia Articles Integer square root The definition of "integer square root" could be found here Methods of computing square roots An algorithm that does "bit magic" could be found here [ Trial 1 : Using Library Function ] Code isqrt(N) when erlang:is_integer(N), N >= 0 -> erlang:trunc(math:sqrt(N)). Problem This implementation uses the sqrt() function from the C library, so it does not work with arbitrarily large integers (Note that the returned result does not match the input. The correct answer should be

Recently I was profiling a program in which the hotspot is definitely this double d = somevalue(); double d2=d*d; double c = 1.0/d2 // HOT SPOT The value d2 is not used after because I only need value c. Some time ago I've read about the Carmack method of fast inverse square root, this is obviously not the case but I'm wondering if a similar algorithms can help me computing 1/x^2. I need quite accurate precision, I've checked that my program doesn't give correct results with gcc -ffast-math option. (g++-4.5) The tricks for doing fast square roots and the like get their performance by