Questions tagged [collision-detection]
Use this tag for questions about detecting the intersection of two or more objects.
138 questions
-2 votes
0 answers
37 views
Related precise SAT encoding of SHA-256. [closed]
Respected mathematicians, I would like to know if there is any GitHub repository that accurately converts SHA-family algorithms into SAT problems. So far, I found the SAT encoder by Saeed Nataj to be ...
1 vote
0 answers
70 views
Exclude a triangle from another triangle
Context: I'm making a video game with walls and objects that can go on (like a picture) or in (like a window or door) a wall. Objects that are in a wall make a hole in the geometry of the wall. For ...
- 123
1 vote
0 answers
31 views
Conditional probability of collision in keyed functions output
Suppose we have a set $X$. For definiteness, let $X=\{0,1\}^l$ for $l \in \mathbb{N}$. Obviously, $|X|=2^l$ in such case. Let $f:X^s \times X^n \to X^n$ be a function. Let $f_i : X^s \times X^n \to X$ ...
- 111
1 vote
0 answers
62 views
Probability of a collision in function that maps each prime $p$ to the range $[p]\times[p]$.
I am looking for an approximation of \begin{align*} P(x)=1-\prod_{i=1}^{\pi(x)}\frac{p_i^2-i+1}{p_i^2}, \end{align*} where $p_i$ is the $i$th prime and $\pi(x)$ is the prime counting function. This is ...
0 votes
2 answers
140 views
Center position of an orthogonal rectangle that has a side or corner touching a circumference
I need to find how distant the center of an orthogonal rectangle is from the center of a circle, given a specific angle. The dimensions of the rectangle are proportional to the circle radius, so they ...
- 103
0 votes
0 answers
52 views
Scaling a threshold for anomaly detection depending on the sample size
I'm trying to study and test 32-bit hash functions - specifically probability of collision (repeated results for different inputs). And I'm struggling in defining a threshold for outliers/anomalies, ...
- 101
0 votes
0 answers
160 views
Determining if two particles collide in a 2d container
I'm trying to determine if two particles collide within a certain period of time in a 2D container. Given the positions and velocities of the particles, I know a formula to determine if there is a ...
- 26
1 vote
0 answers
47 views
Rounding error accumulation and workaround. Collision detection.
I do not know, fellows, how best to describe my problem. But I will try my best. I think this question is more for mathematicians than programmers. There is 2 objects (fig.1): One object is a wall (...
- 107
1 vote
1 answer
464 views
Detect Collision Point of Two Spheres?
Let's suppose I have two spheres of equal radii in a 3D space, one that's moving along a straight line with a constant speed, and one that's stationary, as such: Where $d$ is the straight line along ...
- 161
0 votes
0 answers
189 views
How can I check if a rotated rect intersects a non-rotated rectangle?
I have a rotated retangle and a rectangle. Both are defined by their corners (however, for the non-rotated ones I also have access to topLeft, topRight, etc). Is there a way I can check if they ...
- 113
0 votes
1 answer
97 views
Collisions in random functions
Consider a random function, from $\{0, 1\}^n$ to $\{0, 1\}^n$. For a particular string $y^{*} \in \{0, 1\}^n$ in the image of the function, in expectation over the randomness, how many strings in the ...
- 407
0 votes
0 answers
152 views
General Ellipse Intersection Detection
I'm doing some research on my own to find a method to check if two ellipses intersect. So let's say we have the fallowing two general equations: $$ ƒ_{1}\ :\ A_{1}x^{2}\ +\ B_{1}xy\ +\ C_{1}y^{2}\ +\...
- 193
0 votes
1 answer
112 views
Collision of a linearly moving object and a linearly accelerating object
There are two objects on a plane: a stationary object P1 and a moving object P2 moving at a known costant velocity vector v2. I also know the relative position vector d. img1 I want to calculate the ...
0 votes
1 answer
78 views
Collisions in a Sample [closed]
Based on birthday paradox; Let $d$ be the set of elements randomly chosen from a set of $n$ distinct elements then a) What is expected number of unique elements in $d$ (remaining will be repetition of ...
- 143
5 votes
1 answer
322 views
Birthday paradox - variance, parallelisation, simple proofs?
I am looking for an elementary proof of the fact that expected time for finding a colision with $n$ bins is $\sqrt{\frac{\pi n}{2}} + O(1)$. The proof that I knows relies on the asymptotic expansion ...
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