sqrt

问题 What is the difference in CPU cycles (or, in essence, in 'speed') between x /= y; and #include <cmath> x = sqrt(y); EDIT: I know the operations aren't equivalent, I'm just arbitrarily proposing x /= y as a benchmark for x = sqrt(y) 回答1: The answer to your question depends on your target platform. Assuming you are using most common x86 cpus, I can give you this link http://instlatx64.atw.hu/ This is a collection of measured instruction latency (How long will it take to CPU to get result after

问题 I wrote a quick code for factorizing formulas, however the line that takes creates the square root of D doesn’t work. The line is line 10. Any help is appreciated. using System; public class MainClass { //Source Numbers public int A = 1; public int B = 3; public int C = 9; //Calculation Numbers public float Di; public static double Sqrt(double Di); //This is the faulted line. //Answers public float X; public float X1; public float X2; public static void Main() { Console.Writeline("D=", Di); /

问题 Under visual 2012 how can I call the sqrtsd asm function in a c++ project I can't find it via google something like : double mySqrt(double val) { __asm { ... sqrstd... } } EDIT: in 32bit mode 回答1: I think doing this is a somewhat academic excercise, as it's unlikely to have any actual benefit, and quite likely a penalty. However: double mySqrt(double val) { double retu; __asm { sqrtsd xmm1, val movsd retu, xmm1 } return retu; } 回答2: Why not using sqrt function http://www.cplusplus.com

问题 This question already has answers here : Undefined reference to `sin` [duplicate] (4 answers) Closed 6 years ago . Reading the documentation for math.h, it seems like all I should have to do is include math.h, and use the math functions included, such as sqrt. The problem is I get the following error when trying to use sqrt in my program. I tried math.sqrt, but that did not work, either. Any idea what I am doing wrong? undefined reference to `sqrt' ... #include <stdio.h> #include <math.h> int

问题 This question already has answers here : undefined reference to sqrt (or other mathematical functions) (5 answers) Closed 4 months ago . Part of my program is to calculate sqrt of float number. When I write sqrt(1.0f); I success to compile the program,but when I write sqrt(-1.0f); the compilation fails with undefined reference to 'sqrt' - I suppose that in this case the nan value will be returned... I compile the program uing gcc. When I compile it with visual studio it is compiled

问题 In specific: Im doing some math operations, and the application keeps crashing because a double that is widely used happens to get the value: -1.#IND000000000000 when "some" numbers are sqrt'ed... What is this? Indefinite? Infinite? Too big to fit? Not a perfect Square Root? Is there any way to solve this? Thanks in advance! EDIT: How can i check if a double has this value ? I tried: if (x == 0x-1.#IND000000000000) and other variations but did not work. Is it possible to check to see if a

问题 What causes the problem? from math import sqrt print "a : " a = float(raw_input()) print "b : " b = float(raw_input()) print "c : " c = float(raw_input()) d = (a + b + c)/2 s = sqrt(d*(d-a)*(d-b)*(d-c)) print "a+b+c =", a, b, c print "Distr. =", d*2, "Area =", s Error: Traceback (most recent call last): File "C:/Python27/fájlok/háromszög terület2.py", line 11, in <module> s = sqrt(d*(d-a)*(d-b)*(d-c)) ValueError: math domain error 回答1: The problem is that the Heron's formula holds good only

问题 I am looking for the best inverse square root algorithm for fixed point 16.16 numbers. The code below is what I have so far(but basically it takes the square root and divides by the original number, and I would like to get the inverse square root without a division). If it changes anything, the code will be compiled for armv5te. uint32_t INVSQRT(uint32_t n) { uint64_t op, res, one; op = ((uint64_t)n<<16); res = 0; one = (uint64_t)1 << 46; while (one > op) one >>= 2; while (one != 0) { if (op

问题 I practice for an exam in Java. One of the questions I faced today is: Given an array with n numbers, I need to check if there are 2 subarrays(doesn't have to be equal) that their multiplication equals - if there are, will return true, else false. for example : if the array is : {2,15,3,4,2,5} - will return True if the array is : {2,4,6,2,3,4} - will return False. the answer must be recursive, without any loops. so I thought that if there are 2 sub arrays that their multiplication equal it

问题 Consider the following code: #include <cmath> #include <cstdio> const int COUNT = 100000000; int main() { double sum = 0; for (int i = 1; i <= COUNT; ++i) sum += sqrt(i); printf("%f\n", sum); return 0; } It runs 5.5s on my computer. However, if I change sqrt into std::sqrt , It will run only 0.7s. I know that if I use sqrt , I'm using the function from C library, and if I use std::sqrt , I'm using the one in <cmath> . But <cmath> doesn't define one for int , and if I change the type of i into