Float.NaN == Float.NaN
Use Float.isNaN to check for NaN values.
floating-point
Status of __STDC_IEC_559__ with modern C compilers
I believe __STDC_IEC_559__ relies on some library features and can’t be defined solely by the compiler. See this post for some information. This is not uncommon for C — the compiler and the C library must sometimes cooperate in order to implement the entire standard. What you’re asking depends on the compiler. I think you … Read more
Find unique elements of floating point array in numpy (with comparison using a delta value)
Another possibility is to just round to the nearest desirable tolerance: np.unique(a.round(decimals=4)) where a is your original array. Edit: Just to note that my solution and @unutbu’s are nearly identical speed-wise (mine is maybe 5% faster) according to my timings, so either is a good solution. Edit #2: This is meant to address Paul’s concern. … Read more
Generate random float64 numbers in specific range using Golang
Simply use rand.Float64() to get a random number in the range of [0..1), and you can map (project) that to the range of [min..max) like this: r := min + rand.Float64() * (max – min) And don’t create a new rand.Rand and / or rand.Source in your function, just create a global one or use … Read more
How to perform round to even with floating point numbers
Just to make sure we’re on the same page, G is the most significant bit of the three, R comes next and S can be thought of as the least significant bit because its value partially represents the even less significant bits that have been truncated in the calculations. These three bits are only used … Read more
How to produce a NaN float in c?
Using floating point numbers, 0.0 / 0.0 isn’t a “divide by zero” error; it results in NaN. This C program prints -nan: #include <stdio.h> int main() { float x = 0.0 / 0.0; printf(“%f\n”, x); return 0; } In terms what NaN looks like to the computer, two “invalid” numbers are reserved for “signaling” and … Read more
gcc -O0 still optimizes out “unused” code that should raise an FP exception. Is there a compile flag to change that?
Why does gcc not emit the specified instruction? A compiler produces code that must have the observable behavior specified by the Standard. Anything that is not observable can be changed (and optimized) at will, as it does not change the behavior of the program (as specified). How can you beat it into submission? The trick … Read more
What is the difference between std::min/std::max and fmin/fmax?
fmin and fmax are specifically for use with floating point numbers (hence the “f”). If you use it for ints, you may suffer performance or precision losses due to conversion, function call overhead, etc. depending on your compiler/platform. std::min and std::max are template functions (defined in header <algorithm>) which work on any type with a … Read more