How to fix ‘RuntimeWarning: divide by zero encountered in double_scalars’

Those are not actual errors, but warnings. They are there because you are trying to divide something by zero. Namely, you are setting M[0] = 0 and then dividing by M[0] (at first iteration, where m = 0) and same for P[0]. The question is, what do you want the first values to be? Maybe a solution would be initialize the … Read more

Calculate distance between two latitude-longitude points? (Haversine formula)

This link might be helpful to you, as it details the use of the Haversine formula to calculate the distance. Excerpt: This script [in Javascript] calculates great-circle distances between the two points – that is, the shortest distance over the earth’s surface – using the ‘Haversine’ formula.

Probability of hash collision

Let’s imagine we have a truly random hash function that hashes from strings to n-bit numbers. This means that there are 2n possible hash codes, and each string’s hash code is chosen uniformly at random from all of those possibilities. The birthday paradox specifically says that once you’ve seen roughly √(2k) items, there’s a 50% chance … Read more

How to save decimal in java

Initialize your variable with an expression that evaluates to a double rather than an int: Otherwise the expression is done using integer arithmetic (which ends up truncating the result). That truncated result then gets converted to a double.

Mapping a numeric range onto another

Let’s forget the math and try to solve this intuitively. First, if we want to map input numbers in the range [0, x] to output range [0, y], we just need to scale by an appropriate amount. 0 goes to 0, x goes to y, and a number t will go to (y/x)*t. So, let’s reduce your problem to the above simpler problem. … Read more