absolute-value

How do I get the absolute value of a number without using math.abs? This is what I have so far: function absVal(integer) { var abs = integer * integer; return abs^2; } You can use the conditional operator and the unary negation operator : function absVal(integer) { return integer < 0 ? -integer : integer; } You can also use >> (Sign-propagating right shift) function absVal(integer) { return (integer ^ (integer >> 31)) - (integer >> 31);; } Note: this will work only with integer Since the absolute value of a number is "how far the number is from zero", a negative number can just be "flipped"

I am working with an Oscillator that fluctuates between 10.000000 and -10.000000 The value changes say every 5 minutes. I want to find the difference between the current value and the value of 5 minutes ago. Here is my logic. 1 bar ago (1BA)= -.2 Current bar (CB) = .3 Wouldn't I get a value of 1 if I did something like: Abs(CB) - Abs(1BA) = .3 - .2 = 1 Whereas: Abs(CB- 1BA) = .3 - -.2 = 5 I want to simply calculate the difference between the move of the oscillator from one time frame to another. Am I applying the Abs with the right logic in mind? Here is my actual code, please assume my method

I am currently writing some glsl like vector math classes in C++, and I just implemented an abs() function like this: template<class T> static inline T abs(T _a) { return _a < 0 ? -_a : _a; } I compared its speed to the default C++ abs from math.h like this: clock_t begin = clock(); for(int i=0; i<10000000; ++i) { float a = abs(-1.25); }; clock_t end = clock(); unsigned long time1 = (unsigned long)((float)(end-begin) / ((float)CLOCKS_PER_SEC/1000.0)); begin = clock(); for(int i=0; i<10000000; ++i) { float a = myMath::abs(-1.25); }; end = clock(); unsigned long time2 = (unsigned long)((float)

Is the std::abs() function well defined for ALL arithmetic types in C++11 and will return |x| with no problem of approximation? A weird thing is that with g++4.7, std::abs(char) , std::abs(short int) , std::abs(int) , std::abs(long int) and std::abs(long long int) seem to return a double (on the contrary of : http://en.cppreference.com/w/cpp/numeric/math/abs ). And if the number is casted to a double, we could have some approximation error for very large number (like -9223372036854775806LL = 2^63-3 ). So do I have the guarantee that std::abs(x) will always return |x| for all arithmetic types ?

I am trying to understand how the following code snippet works. This program uses SIMD vector instructions (Intel SSE) to calculate the absolute value of 4 floats (so, basically, a vectorized "fabs()" function). Here is the snippet: #include <iostream> #include "xmmintrin.h" template <typename T> struct alignas(16) sse_t { T data[16/sizeof(T)]; }; int main() { sse_t<float> x; x.data[0] = -4.; x.data[1] = -20.; x.data[2] = 15.; x.data[3] = -143.; __m128 a = _mm_set_ps1(-0.0); // ??? __m128 xv = _mm_load_ps(x.data); xv = _mm_andnot_ps(a,xv); // <-- Computes absolute value sse_t<float> result;

It appears, that in 32bit OS ip2long returns signed int, and in 64bit OS unsigned int is returned. My application is working on 10 servers, and some are 32bit and some are 64bit, so I need all them to work same way. In PHP documentation there is a trick to make that result always unsigned, but since I got my database already full of data, I want to have it signed. So how to change an unsigned int into a signed one in PHP? PHP does not support unsigned integers as a type, but what you can do is simply turn the result of ip2long into an unsigned int string by having sprintf interpret the value