Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers. This question does not appear to be about programming within the scope defined in the help center. Closed 5 months ago. The community reviewed whether to reopen this question 5 months ago and left it closed: Original close reason(s) were … Read more
In the output layer of a neural network, it is typical to use the softmax function to approximate a probability distribution: This is expensive to compute because of the exponents. Why not simply perform a Z transform so that all outputs are positive, and then normalise just by dividing all outputs by the sum of … Read more
So I am trying to figure out how to take a range of numbers and scale the values down to fit a range. The reason for wanting to do this is that I am trying to draw ellipses in a java swing jpanel. I want the height and width of each ellipse to be in … Read more
I need to generate a uniformly random point within a circle of radius R. I realize that by just picking a uniformly random angle in the interval [0 … 2π), and uniformly random radius in the interval (0 … R) I would end up with more points towards the center, since for two given radii, … Read more
There have been several questions posted to SO about floating-point representation. For example, the decimal number 0.1 doesn’t have an exact binary representation, so it’s dangerous to use the == operator to compare it to another floating-point number. I understand the principles behind floating-point representation. What I don’t understand is why, from a mathematical perspective, … Read more
Having a list of points, how do I find if they are in clockwise order? For example: point[0] = (5,0) point[1] = (6,4) point[2] = (4,5) point[3] = (1,5) point[4] = (1,0) would say that it is anti-clockwise (or counter-clockwise, for some people). 23 Answers 23
I am reading this book (NLTK) and it is confusing. Entropy is defined as: Entropy is the sum of the probability of each label times the log probability of that same label How can I apply entropy and maximum entropy in terms of text mining? Can someone give me a easy, simple example (visual)? 7 … Read more
How do I calculate distance between two GPS coordinates (using latitude and longitude)? 31 Answers 31 Calculate the distance between two coordinates by latitude and longitude, including a Javascript implementation. West and South locations are negative. Remember minutes and seconds are out of 60 so S31 30′ is -31.50 degrees. Don’t forget to convert degrees … Read more
I can’t get my head around this, which is more random? rand() OR: rand() * rand() I´m finding it a real brain teaser, could you help me out? EDIT: Intuitively I know that the mathematical answer will be that they are equally random, but I can’t help but think that if you “run the random … Read more
A question I got on my last interview: Design a function f, such that: f(f(n)) == -n Where n is a 32 bit signed integer; you can’t use complex numbers arithmetic. If you can’t design such a function for the whole range of numbers, design it for the largest range possible. Any ideas? 119 s … Read more
