This is one of those highly-application specific things. It may help in some cases and not in others. (In the vast majority of cases, a straight-forward multiplication is still best.) The “intuitive” way of doing this is just to extract the bits into a 64-bit integer and add the shift value directly into the exponent. … Read more
Some template metaprogramming with SFINAE, perhaps. #include <type_traits> template <typename T, typename std::enable_if<std::is_unsigned<T>::value && (sizeof(T) <= sizeof(unsigned int)) , int>::type = 0> T safe_multiply(T a, T b) { return (unsigned int)a * (unsigned int)b; } template <typename T, typename std::enable_if<std::is_unsigned<T>::value && (sizeof(T) > sizeof(unsigned int)) , int>::type = 0> T safe_multiply(T a, T b) { … Read more
In [161]: pd.DataFrame(df.values*df2.values, columns=df.columns, index=df.index) Out[161]: col1 col2 col3 1 10 200 3000 2 10 200 3000 3 10 200 3000 4 10 200 3000 5 10 200 3000
decimal stores 28 or 29 significant digits (96 bits). Basically the mantissa is in the range -/+ 79,228,162,514,264,337,593,543,950,335. That means up to about 7.9…. you can get 29 significant digits accurately – but above that you can’t. That’s why both the 8 and the 9 go wrong, but not the earlier values. You should only … Read more
long oneYearWithL = 1000*60*60*24*365L; long oneYearWithoutL = 1000*60*60*24*365; Your first value is actually a long (Since 365L is a long, and 1000*60*60*24 is an integer, so the result of multiplying a long value with an integer value is a long value. But 2nd value is an integer (Since you are mulitplying an integer value with … Read more
.toFixed() is best solution.It will keep only two digits after dot. Exp 1: var value = 3.666; value.toFixed(2); //Output : 3.67 Exp 2: var value = 3.0000; value.toFixed(2); //Output : 3.00
If you’re using gcc and the version you have supports 128 bit numbers (try using __uint128_t) then performing the 128 multiply and extracting the upper 64 bits is likely to be the most efficient way of getting the result. If your compiler doesn’t support 128 bit numbers, then Yakk’s answer is correct. However, it may … Read more
The main problem is that you never initialize result (to 1), so this: result=$(($result * $input)) is equivalent to this: result=$(( * $input)) which is not a valid arithmetic expression.
You’ve made 3 references to the same list. >>> a = b = [] >>> a.append(42) >>> b [42] You want to do this: P = [[()] * 3 for x in range(3)]
Operator ^ is a bitwise operator, which does bitwise exclusive or. The power operator is **, like 8**3 which equals to 512.