The simple answer is because 3*0.1 != 0.3 due to quantization (roundoff) error (whereas 4*0.1 == 0.4 because multiplying by a power of two is usually an “exact” operation). Python tries to find the shortest string that would round to the desired value, so it can display 4*0.1 as 0.4 as these are equal, but … Read more
Besides the assert(NaN==NaN); case pointed out by kmdreko, you can have situations with x87-math, when 80bit floats are temporarily stored to memory and later compared to values which are still stored inside a register. Possible minimal example, which fails with gcc9.2 when compiled with -O2 -m32: #include <cassert> int main(int argc, char**){ float x = … Read more
5.55 % 1 Keep in mind this won’t help you with floating point rounding problems. I.e., you may get: 0.550000000001 Or otherwise a little off the 0.55 you are expecting.
A value of the double floating-point type is represented like so: and it can be seen as two 32-bit integers; now, the int taken in all the versions of your code (supposing it’s a 32-bit int) is the one on the right in the figure, so what you are doing in the end is just … Read more
As others have mentioned, you’ll probably want to use the BigDecimal class, if you want to have an exact representation of 11.4. Now, a little explanation into why this is happening: The float and double primitive types in Java are floating point numbers, where the number is stored as a binary representation of a fraction … Read more
With Python < 3 (e.g. 2.6 [see comments] or 2.7), there are two ways to do so. # Option one older_method_string = “%.9f” % numvar # Option two newer_method_string = “{:.9f}”.format(numvar) But note that for Python versions above 3 (e.g. 3.2 or 3.3), option two is preferred. For more information on option two, I suggest … Read more
If you do it like this they should be the same. But note that a characteristic of floating-point values is that calculations which seem to result in the same value do not need to actually be identical. So if $a is a literal .17 and $b arrives there through a calculation it can well be … Read more
The IEEE 754 format has one bit reserved for the sign and the remaining bits representing the magnitude. This means that it is “symmetrical” around origo (as opposed to the Integer values, which have one more negative value). Thus the minimum value is simply the same as the maximum value, with the sign-bit flipped, so … Read more
Output of perldoc -q round Does Perl have a round() function? What about ceil() and floor()? Trig functions? Remember that int() merely truncates toward 0. For rounding to a certain number of digits, sprintf() or printf() is usually the easiest route. printf(“%.3f”, 3.1415926535); # prints 3.142 The POSIX module (part of the standard Perl distribution) … Read more
Note: the Nintendo 64 does have a 64-bit processor, however: Many games took advantage of the chip’s 32-bit processing mode as the greater data precision available with 64-bit data types is not typically required by 3D games, as well as the fact that processing 64-bit data uses twice as much RAM, cache, and bandwidth, thereby … Read more