Programming questions that are significantly affected or best defined by the underlying mathematics of the problem.
2
votes
1answer
202 views
Subtractive color mixing algorithm
Here is my problem:
I have a set of 'n' colors including the primary colors and their codes in hexadecimal. Now given another color 'x' I wonder if it's actually possible to come up with a mix ...
-3
votes
3answers
207 views
More Accurate Random in C [closed]
I have 3 IPs and every IP has a weight, I want to return the IP's according to its weights using the random function. For example if we have 3 IP's
X with weight 3
Y with weight 3
and Z with weight ...
0
votes
0answers
50 views
How to process components of a matrix that are obtained by singular value decomposition so as to find weightage?
I am writing an application that needs to find weightage of words in a document.
For this I am using the principles and techniques of Information retrieval. I programmed to find information about ...
0
votes
0answers
29 views
How to parse polynomials from a string equation [migrated]
I am wondering, given the string n*3/7+9-5, I could get the Polynomial from that, as an array or a string, such as [4, 3/7]. How should I go about doing this?
Also, There is a library allows me to ...
-3
votes
3answers
171 views
Which if statement requires less computation?
I have
if (!b && c || a && c)
//do action a
else
//...
Due to some internal relationship between a, b, and c. !b && c || a && c is proved to be equivalent to (! ...
2
votes
3answers
401 views
Why does division and multiplication by 2 use the shift operator rather than division operator?
While looking at the code in C for division/multiplication by 2, it is found that shift operator is used rather than division operator. What is the advantage of using shift over division operator?
1
vote
3answers
257 views
Why is float the default in the majority of languages?
In programming languages, for represent numbers you have (mainly) two types: Int(s) and floats.
The us of Int is very easy. However floats cause a lot of unexpected surprises:
...
1
vote
2answers
120 views
How fast should a Python factoring script be?
Just how efficient is "good enough" for all intents and purposes? I wrote a script to simply list off all numbers that divide into an input, x, as pairs (i, n//i) and was just curious how efficient I ...
1
vote
0answers
77 views
Reversing a summation algorithum [migrated]
I have a bit of a math problem on a hobby project of mine, and I was hoping some of the experts here could give me some guidance.
I am preforming some calculations on a set of numbers where the ...
0
votes
0answers
10 views
Using the Pochhammer Symbol in Matlab [migrated]
I've tried to use a script that evaluates the Pochhammer symbol (rising factorial) in Matlab, but it fails to evaluate Pochhammer(x,n) whenever x is a negative number even though the expression is ...
4
votes
5answers
407 views
When comparing floats, what do you call the threshold of difference?
I'm comparing floats in Java right now and the simplest formula is:
Math.abs(a - b) < THRESHOLD
When naming your variable for the threshold of difference, should you name it delta or epsilon? ...
10
votes
4answers
335 views
Why is mod (%) a fundamental mathematical operator in many programming languages?
Is there a reason, historical or otherwise, why the modulus operator is part of a small set of standard operators in what seems like many languages? (+, -, *, / and %, for Java and C, with ** in Ruby ...
10
votes
7answers
658 views
Web Developer and Math [duplicate]
I have just learned HTML/CSS and I practice everything I read to make it more understandable to me and I really enjoy it. My goal is to be a Modern Web Developer both front and back-end, so I won't ...
6
votes
1answer
121 views
Bin sorting problem - Please help categorize
I have a problem I am developing a solution for and currently I solve it with a brute force solution that checks all possibilities. It works for small numbers of bins but I'd like to work with a ...
13
votes
2answers
401 views
Trying to understand the 2N lnN compares for quicksort
I was going through the analysis of quicksort in Sedgewick's Algorithms book. He creates the following recurrence relation for number of compares in quicksort while sorting an array of N distinct ...
0
votes
1answer
138 views
Sum of divisors of numbers of the range ~ 10^6
I was trying to find the sum of divisors of numbers upto 106. The test cases are like of the order of 105. I have done some pre processing like
int divisors(int num)
{
int sum=0;
for(int ...
0
votes
3answers
178 views
Using Power of 2 numbers to represent types
Let's say that we have some values, represented by power of 2:
TYPE_1 = 1
TYPE_2 = 2
TYPE_3 = 4
TYPE_4 = 8
...
I need to store some of these types in one value.
Example:
To represent TYPE_1 with ...
0
votes
1answer
135 views
Python — Time complexity of built-in functions versus manually-built functions in finite fields
Generally, I'm wondering about the advantages versus disadvantages of using the built-in arithmetic functions versus rolling your own in Python.
Specifically, I'm taking in GF(2) finite field ...
14
votes
4answers
749 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 ...
4
votes
2answers
168 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 ...
0
votes
0answers
85 views
What kind of maths do I need to become an excellent programmer [duplicate]
I am looking to become a app/video game developer or a website developer. What kind of maths do I need to know and do I have to know it well. Do I need to know calculus, statistics and modeling, what ...
4
votes
2answers
371 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 ...
0
votes
0answers
125 views
What kind of math do I need to become a better developer and programmer? [duplicate]
I'm at a community college currently and while our curriculum is pretty good, it lacks math or any real theory. If I ever want to create an algorithm for anything, I'm screwed. I'm essentially a code ...
3
votes
1answer
168 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 ...
1
vote
0answers
194 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 ...
5
votes
1answer
172 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 ...
1
vote
1answer
140 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 ...
2
votes
4answers
99 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 ...
2
votes
2answers
290 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 ...
1
vote
4answers
340 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 ...
0
votes
3answers
141 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 ...
2
votes
2answers
1k 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 ...
4
votes
3answers
277 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 ...
2
votes
7answers
769 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 ...
0
votes
2answers
128 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 ...
2
votes
3answers
544 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 ...
3
votes
3answers
210 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 ...
0
votes
1answer
233 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 ...
3
votes
2answers
130 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 ...
0
votes
1answer
125 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 ...
9
votes
5answers
656 views
Interview puzzle on traveling on a line segment
Here's an interesting question I came upon:
Let's just say 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 ...
2
votes
1answer
110 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 ...
0
votes
1answer
94 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 ...
2
votes
1answer
424 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 = [];
...
-1
votes
1answer
768 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 ...
1
vote
1answer
1k 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 ...
3
votes
3answers
369 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 ...
0
votes
4answers
500 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 ...
1
vote
3answers
1k 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 ...
1
vote
4answers
216 views
LaTeX-like display programming environment
I used to be a hobbyist programmer, but now I'm also a fairly experienced physicist and find myself programming to solve certain problems quite a lot. In physics, we use variables with superscripts, ...
