Questions tagged [algorithms]
A description of the specific steps needed to solve a particular problem in an unambiguous way, expressed in an abstract form.
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Rule-Based Link Prediction for Social Network [migrated]
Relevance to Site
I believe this question is suitable for the Computational Sciences Stack Exchange site as it pertains to the implementation of a graph algorithm. According to this widely accepted ...
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Guidelines for image detection model for statis sample
I have 20,000 plus images of art (paintings, sculptures, jars, etc). My goal is creating a computer vision model that, from an input (image), identifies the exact same piece of art and returns its id, ...
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Advanced computing on FPGA
I am an absolute beginner in the FPGA topic (so far I have only implemented a couple of simple logic gates in Verilog and simulated them in ModelSim). I studied digital electronics, logic elements, ...
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What is fastest method for finding the minimum and maximum eigenvalues of a (possibly very large) symmetric matrix?
What is the best way to find the extreme eigenvalues - in order to find the spectral radius - of a general real dense symmetric matrix?
Looking at similar questions e.g.: What's the most efficient ...
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Non-uniform Gaussian spaced vector
I am working on a Fortran code that uses a uniformly spaced grid in two directions (x,y). Which works fine, but when I need to study a certain problem with good resolution, I need to increase the ...
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An alternative to Levenberg–Marquardt algorithm
When trying to solve for a (over)determined non-linear least square method:
$$\underset{x}{\min}||f(x)||^2_2, f: \mathbb{R}^n \rightarrow \mathbb{R}^m, x\in \mathbb{R}^n, m\geq n$$
we use the Gauss-...
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Standard deviation for online scenarios
Let's suppose you have to create an online algorithm $f(x_i)$ that will return
the average ($\mu$); And
the standard deviation ($\sigma$);
Of numbers $x_0, \dots, x_i$.
A straightforward approach ...
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Find clusters with threshold for number of members
I need to find clusterization of some daily weather data,
and the number of days in any cluster should be more than some threshold (e.g. 30).
So if some cluster has less members, it has to be merged ...
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Computing the Fiedler vector of a large, sparse graph
I have a sparse, undirected and unweighted graph $G$ of size $n$, with $n$ on the order of say several million. I would like to compute the Fiedler vector $f$ of $G$, which is the eigenvector ...
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Regarding the difference between Metropolis-Hastings and Wolff algorithm (synchronous vs asynchronous) applied to Ising Model?
I am trying to self-learn concepts at the intersection of physics and programming. When reading up on the Ising Model, I find that the typical programming tutorial (such as this one) covers the ...
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Gradient descent for solving polynomial equations while encouraging variables to be nonzero
I would like to use gradient descent to "randomly sample" solutions to a set of homogeneous polynomial equations. Because the equations are homogeneous, setting all variables to 0 is a valid ...
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Why algorithm is computational procedure?
I am reading a book: Introduction to Algorithms.
In the first chapter is itself, Algorithm is defined as ...
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Methods for delaying the "break" in non-linear least squares optimisation when the step size gets too small?
I am using the Levenberg-Marquardt method for calibration purposes. Typically, the RMSE of my calibration looks like:
I want to break the algorithm when the algorithm step-updates start to slow down, ...
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More stable algorithm to calculate `sqrt(a^2 + b^2) - abs(a)` in MatLab
Suppose we want to calculate $\sqrt{a^2+b^2}-|a|$ in MatLab. Using sqrt(a^2 + b^2) - abs(a) will have some problems:
If a or <...
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stupid + stupid = brilliant in scientific computing
I'm interested in examples of very effective methods in scientific computing that are the sum or naive combination of very ineffective or bad ones.
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