#include <iostream> #include <stdlib.h> #include <iomanip> int main() { int a = 5; int b = 10; std::cout << std::fixed; std::cout << std::setprecision(4); std::cout << (float)a/(float)b << “\n”; return 0; } You need to pass std::fixed manipulator to cout in order to show trailing zeroes.
The precision is fixed, which is exactly 53 binary digits for double-precision (or 52 if we exclude the implicit leading 1). This comes out to about 15 decimal digits. The OP asked me to elaborate on why having exactly 53 binary digits means “about” 15 decimal digits. To understand this intuitively, let’s consider a less-precise … Read more
pow works with double numbers. These represent numbers of the form s * 2^e where s is a 53 bit integer. Therefore double can store all integers below 2^53, but only some integers above 2^53. In particular, it can only represent even numbers > 2^53, since for e > 0 the value is always a … Read more
This really has nothing to do with Python – you’d see the same behavior in any language using your hardware’s binary floating-point arithmetic. First read the docs. After you read that, you’ll better understand that you’re not adding one one-hundredth in your code. This is exactly what you’re adding: >>> from decimal import Decimal >>> … Read more
Q: is it possible to specify a dtype for random numbers when I create them. A: No it isn’t. randn accepts the shape only as randn(d0, d1, …, dn) Simply try this: x = np.random.randn(10, 10).astype(‘f’) Or define a new function like np.random.randn2 = lambda *args, dtype=np.float64: np.random.randn(*args).astype(dtype) x = np.random.randn2(10, 10, dtype=”f”) If you … Read more
It’s not possible to natively deal with a 21-digit precision number in JavaScript. JavaScript only has one kind of number: “number”, which is a IEEE-754 Double Precision (“double”) value. As such, parseFloat in JavaScript is the equivalent of a “parse double” in other languages. However, a number/”double” only provides 16 significant digits (decimal) of precision … Read more
You can use setScale() e.g. double d = … BigDecimal db = new BigDecimal(d).setScale(12, BigDecimal.ROUND_HALF_UP);
I would use: val, idx = min((val, idx) for (idx, val) in enumerate(my_list)) Then val will be the minimum value and idx will be its index.
From the C++ Standard The type of a floating literal is double unless explicitly specified by a suffix. The suffixes f and F specify float, the suffixes l and L specify long double. It is interesting to compare with corresponding paragraph of the C Standard. In C there is used term floating constant instead of … Read more
I recommend @Jens Gustedt hexadecimal solution: use %a. OP wants “print with maximum precision (or at least to the most significant decimal)”. A simple example would be to print one seventh as in: #include <float.h> int Digs = DECIMAL_DIG; double OneSeventh = 1.0/7.0; printf(“%.*e\n”, Digs, OneSeventh); // 1.428571428571428492127e-01 But let’s dig deeper … Mathematically, the … Read more