# Questions tagged [math]

Programming questions that are significantly affected or best defined by the underlying mathematics of the problem.

254 questions
3k views

### Documenting mathematical logic in code

Sometimes, although not often, I have to include math logic in my code. The concepts used are mostly very simple, but the resulting code is not - a lot of variables with unclear purpose, and some ...
5k views

### Array Multiplication and Division

I came across a question that (eventually) landed me wondering about array arithmetic. I'm thinking specifically in Ruby, but I think the concepts are language independent. So, addition and ...
3k views

### Does learning to play an instrument improve programming ability? [closed]

I've seen plenty of questions asking if listening to music boosts productivity, etc. but I haven't been able to find one about performing music. Learning to play the piano has been on my to-do list ...
318 views

### Finding maximum number of congruent numbers

Let's say we have a multiset (set with possible duplicates) of integers. We would like to find the size of the largest subset of the multiset such that all numbers in the subset are congruent to each ...
313 views

### Optimization algorithm, how to develop this problem

I have a situation where I would like your input and think over / solve algorithm. The specs There are inventories with a specified amount of capacity. 'X (width) and Y (time)' creates ...
1k views

### What is the difference between a combinator and function chaining?

So from what I've read about combinators I can't quite tell how they're different from simply chaining function calls. I know I must be missing something but I'm not figuring out what I'm missing. I ...
577 views

### Pairwise testing, not possible to say which combinations is faulty?

Let's say I have 4 (A,B,C,D) parameters with 3 possible values, also 81 unique combinations. With e.g. orthogonal array, I will end up with 9 test cases, each combining 3 pairs. But that means that if ...
134 views

### Find how the data has been processed

Well this has been a question I have puzzled about for a long time: Suppose I have a dictionary of input:output like: This {2: 6, 5: 15, 20: 60, 26: 78, ... 982: 2946, 997: 2991} where ...
2k views

### Transform math formula into code (line-line intersection)

I'm having hard times transforming a math formula to code. I can solve it on the paper easily, but it's hard for me to bring it into code form. Is it generally possible to bring a math formula ...
5k views

### Is there such a thing as truly random? [closed]

I saw a video about random numbers and how the programmer in that video was talking about computers generating pseudo random numbers and that they are not really random. I knew about this. Then he ...
1k views

### algorithm to create all possible column vectors of size N containing only ones and zeroes [closed]

I am a mathematics student and am just starting to learn about programming. I am stuck on a particular program I am trying to write for fun. I want to find an algorithm to create all possible column ...
13k views

### Closest Point of Approach (CPA) mathematical formula in ship radar

I was recently searching for the mathematical formula to find closest point of approach (CPA) between one ship and another ship. I need to apply the formula in my radar ship program and I can't find ...
306 views

### Customer Requirements Contains Equations that Cancel to Nothing

I have a project where the customer requirement specifies a report and contains mathematical equations for the contents of some of the columns on that report. One of the columns on this report is a ...
1k views

### Is (1/(1/x)) always a perfect round trip?

Is the following guaranteed to return true for all numerical and non-zero values of x? bool IsRoundTrip(double x) { double y = 1 / (1 / x); return x == y; } What conditions would cause a ...
259 views

### Tracking scientific error when working with floating-point numbers

Background I hate the way .Net/IEEE-754 handles equality of floating-point numbers (FPNs) (i.e. double, float). It requires the programmer to be prescient with respect to the yet-to-be-determined ...
28k views

### what is a efficient way to find repeating decimal

I am trying to find a efficient algorithm in Java to find the repeating decimal part of two integers a and b where a/b. eg. 5/7 = 0.714258 714258.... I currently only know of the long division ...
515 views

### strategies for dealing with machine epsilon

Say you have a situation where you divide and then multiply a float, and you need to guarantee that it survives macheps (ie multiplication output equals division input). What are known strategies for ...
352 views

### I'm trying to create a visual representation of something, but I don't know what words to use, so I'll try to describe it

My project team is making a site that will use reddit style voting to track users' opinions on various issues, and use the data to create a "heat map". I say heat map in quotes because I'm not sure ...
159 views

### Randomness of wrapped RNG

There are plenty of questions around regarding random number generation, but I couldn't find anything that exactly matched my question. Apologies if I missed one. Most random number generators in ...
993 views

### Algorithm to detect a CLICK within Square range

It might be a simple question but I am looking for optimal solution. I will have numbers printed on a screen and I will be aware of coordinates. Numbers/Symbols will have 4 points(Square) to define ...
929 views

### Interview puzzle on traveling on a line segment

On a number line of length M, where 0 < M <= 1,000,000,000, you given N (1 < N <= 100,000) integer pairs of points. In each pair, the first point represents where an object is currently ...
128 views

### Turning n-dim points into m-dim where m<n and where point-to-point distance deviation is minimized

I want to apply k-means clustering to a (sparse) adjacency graph. For this I need to assign the nodes to a position in an euclidean space. Trivially I can do this by having a space with as many ...
183 views

### How to do scalar multiplication and matrix inverse when variables are of size 1000 bits?

I am doing arithmetic operations on really huge numbers. For example, I am given six variables, a_{11}, a_{12}, a_{21}, a_{22}, x_1, and x_2. Although the above are math terms, these six variables ...
3k views

### Randomly Generate Points in a Spiral Motion using Javascript

So I have a javascript program that currently gets random points, it generates a random x,y,z value around the center point, within the radius r var maxArms = 3; var i = 0; var color = []; ...
7k views

### How to get audio spectrum analysis? [closed]

I need to find or create a tool that analyzes the audio spectrum of a sound file (like a .wav or .mp3). I need to output the "volume" or power of x number of frequency bands and output the data as ...
10k views

### Find the new coordinates using a starting point, a distance, and an angle

Okay, say I have a point coordinate. var coordinate = { x: 10, y: 20 }; Now I also have a distance and an angle. var distance = 20; var angle = 72; The problem I am trying to solve is, if I want ...
2k views

### Date calculation algorithm

I'm working on a project to schedule a machine shop, basically I've got everything covered BUT date calculations, I've got a method called schedule (working on PHP here): public function schedule(\$...
1k views

### Separating merged array of arithmetic and geometric series [closed]

Given an array of positive integers in increasing order. Separate them in two series, an arithmetic sequence and geometric sequence. The given array is such that a solution do exist. The union of ...
4k views

### Calculating 3d rotation around random axis

This is actually a solved problem, but I want to understand why my original method didn't work (hoping someone with more knowledge can explain). (Keep in mind, I've not very experienced in 3d ...
41k views

### How to check if 4 points form a square?

Assume I have 4 points (they are 2-dimension), which are different from each other, and I want to know whether they form a square. How to do it? (let the process be as simple as possible.)
2k views

### how to programtically build a grid of interlocking but random sized squares

I want to create a two dimensional layout of rectangular shapes, a grid made up of random sized cubes. The cubed should fit together and have equal padding or margin (space between). Kind of like a ...
5k views

### Can you use Pi as a crude random number generator?

I recently saw this question over at math.SE. It got me thinking. Could Pi be used as a crude random number generator? I mean the results are well known(how long has pi been computed to now?) but, Pi ...
7k views

### Why use other number bases when programming

My coworkers and I have been bending our minds to figuring out why anyone would go out of their way to program numbers in a base other than base 10. I suggested that perhaps you could optimize longer ...
907 views

### Should Equality be commutative within a Class Hierachy?

It is easy to define the Equals operation in ways that are not commutative. When providing equality against other types, there are obviously situations (in most languages) were equality not being ...
376 views

### What's the normal way machine-learning algorithms are integrated into normal programs?

I'm currently taking a machine learning course for fun, and the course heavily focuses on Matlab/Octave to write the code. One thing mentioned in the course is that, while Matlab/Octave are great for ...
137 views

### Working with vectors and transformations

I am going to write an graphical 2D application that allows user to create polygons and transform them through transformation such as rotation an so on. I was hoping someone can give pro and cons ...
4k views

### Algorithm to calculate trajectories from vector field

I have a two-dimensional vector field, i.e., for each point (x, y) I have a vector (u, v), whereas u and v are functions of x and y. This vector field canonically defines a set of trajectories, i.e. ...
50k views

### How important is Discrete Mathematics for a Computer Scientist? [closed]

As the title says, How important is Discrete Mathematics for a Computer Scientist? Background: I'm pursuing a Master's degree with a focus on fundamentals such as Algorithms, Complexity and ...
377 views

### Dealing with units in arithmetic operations (multiplication and division)

I need to design a function to perform the basic arithmetic operations that are addition (+), subtraction (-), multiplication (x), and division (/) between 2 numbers. That function takes 3 arguments: ...
2k views

### Fractional and Cartesian Coordinates

I have a set of fractional coordinates. I also have a rotation matrix that operates on cartesian coordinates. Does anyone know how I could convert my rotation matrix so I can operate on the ...
2k views

### What Discrete Mathematics topics should the average computer science student know?

I know that Discrete Mathematics is a pretty broad topic that's used in a number of fields but I was just wondering what are some of the topics from it that you would expect an average computer ...
801 views

### 1 to 1 Comparison and Ranking System

I'm looking to create a comparison and ranking system which allows users to view 2 items, click on the one that they feel is the better one and then get presented with 2 more random items and continue ...
8k views

### Can one edit a built-in Python module?

I'm currently learning Python and I'm at the point in the book about using the Math library. I looked on the Python website and noticed the library was a bit scarce and am writing some more useful ...
370 views

### why is a naturally ordered set generated at 9 but not 10 digits

code found at: https://softwareengineering.stackexchange.com/q/158606/44933 Presuming that the problem indicated above is due to the test app and not due specifically to method generateRandomDigits()....
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### How can calculus and linear algebra be useful to a system programmer? [closed]

I found a website saying that calculus and linear algebra are necessary for System Programming. System Programming, as far as I know, is about osdev, drivers, utilities and so on. I just can't figure ...
437 views

### Layout of mathematical views (iOS)

I am trying to figure out the right way to encapsulate graphical information about mathematical objects. It is not simple. For example, a matrix can include square brackets around its entries, or ...
38k views

### get weighted random item

I have, for example, this table +-----------------+ | fruit | weight | +-----------------+ | apple | 4 | | orange | 2 | | lemon | 1 | +-----------------+ I need to return a random ...
813 views

### Long term plan of attack to learn math? [closed]

I am a web-developer with a desire to expand my skill-set to mathematics relevant to programming. As 2nd career, I am stuck in college doing some of the requirements while working. I was hoping the ...