Questions tagged [numerical-methods]

Algorithms which solve mathematical problems by means of numerical approximation (as opposed to symbolic computation).

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2
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1answer
26 views

Vectorized type conversion for autocorrelation

I have a simple task as part of a larger autocorrelation DSP system - to convert from signed 16-bit integer audio samples to floating-point. This part is quite self-contained: ...
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Using Cubature in python [migrated]

I am trying to calculate a seemingly simple integral. Here is the MMA code: ...
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1answer
137 views

Modelling of partcle flow under electric field

This is my first modeling exercise on the particle flow. Recently, I read a paper https://acp.copernicus.org/articles/20/3181/2020/. After reading the paper, thought of modeling it in Python. It seems ...
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1answer
84 views

C++ - Logistic Regression Backpropagation with Gradient Descent

I implemented binary logistic regression for a single datapoint trained with the backpropagation algorithm to calculate derivatives for a gradient descent optimizer. I am primarily looking for ...
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Integrator 2.0: A Simple Integrator in C++17

This is a follow up of A simple definite integrator class of a single variable in C++ I took most of the advice from the user: emma-x and some from user: sudo-rm-rf-slash Here is my fully revised ...
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2answers
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A simple definite integrator class of a single variable in C++

I have written a simple Integrator class in C++17 that can perform either a definite single integration of a single variable or a definite double integration of a ...
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2answers
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Implementing a Steepest Descent Algorithm

I am teaching myself some coding, and as my first "big" project I tried implementing a Steepest Descent algorithm to minimize the Rosenbrock function: $$f(x, y) = 100 (y - x^2)^2 + (1 - x)^2$$ The ...
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1answer
67 views

Linear Interpolation for sorted arrays

I have made a linear interpolation functions as a side project of mine. It assumes everything is sorted before hand - x and f(x) are the same length. I would like to ask for: general recommendations ...
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2answers
36 views

Newton Raphson and polynomials in C

I have the following code, that defines: A polynomial struct with some useful functions. The newton Raphson algorithm for polynomials. and calculates sqrt(2). ...
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Numerical Double Integration using numba and scipy

Please see the following code. I am using it to calculate the double integration. Please help me to improve the code. ...
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3answers
1k views

pure Python Bézier curve implementation

I came up with this recursive pure-Python implementation of De Casteljau's algorithm for computing points on a Bézier curve: ...
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4answers
211 views

Simpson's method for numerically computing the integration of a function

I have implemented the Simpson's rule for numerical integration. Check this video for the implemented function. ...
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1answer
32 views

What would be the computationally faster way to implement this 2D numerical integration?

I am interested in doing a 2D numerical integration. Right now I am using the scipy.integrate.dblquad but it is very slow. Please see the code below. My need is to ...
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2answers
55 views

Implementation of Newton's method of finding root of a function

The following is an implementation of Newton's method of finding root of a function. ...
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2answers
52 views

Simple definite integral calculator

I made this code to compute definite integrals in Processing. It works by getting the rectangle between the maximum value between the previous function value and the current function value, and then I ...
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1answer
63 views

Fortran 90 / openmp heat transfer simulation optimization

I'm a newbie playing around with Fortran 90 and openmp and wrote the code below (a simple 2D heat transfer simulation) for testing purposes. So far I don't see any speedup by using openmp / parallel ...
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2answers
121 views

Get the best rational approximations for any real number in builtin Python

Best rational approximations is a technical term and not subjective. The best rational approximations are the convergents of a value plus it's semi convergents that are closer to the original value ...
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Estimate area of cropped circle with Monte Carlo

I looking around and not finding anything, I developed a simple function for estimating the area of a possibly cropped circle inside a frame. It uses a very basic MC implementation. It is pretty fast ...
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4answers
3k views

IEEE 754 square root with Newton-Raphson

I have an implementation of the sqrt function that uses a combination of IEEE 754, packed bitfields, and the Newton-Raphson algorithm: ...
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2answers
1k views

Mean π: Archimedes vs. Gauss - π computation through generalized means

I've written this simplified code to compute Pi for educational/demonstration purposes. These methods are based upon the generalized means: see a presentation on Pi and the AGM. Archimedes' method ...
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1answer
73 views

Arbitrary precision Euler-Mascheroni constant via a Brent-McMillan algorithm with no math module

Utilizing the below relation, I am able to compute the Euler constant to great precision on a single thread quickly and simply. My process is to compute the natural log via the AGM(utilizing Pi an ...
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1answer
44 views

Euler-Mascheroni Single Thread Speed Improvements

The below code was written to generate γ, for educational purposes. My general methodology is as follows: Compute Gamma via the accepted answer's algorithm here. In order to do this I need to ...
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1answer
174 views

Calculate the Euler-Mascheroni constant without the math module

The below code was written to generate γ, for educational purposes. Single threaded, no functional zeroes required, no binary splitting(which can all be used to compute competitively like y-cruncher, ...
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3answers
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Python π = 1 + (1/2) + (1/3) + (1/4) - (1/5) + (1/6) + (1/7) + (1/8) + (1/9) - (1/10) …1748 Euler

I wrote this code to show that my reddit post is correct. After the first two terms, the signs are determined as follows: If the denominator is a prime of the form 4m − 1, the sign is positive; if ...
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2answers
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Trapezoidal rule for set of data

Here is the question from the book of Mark Newman-Computational Physics Exc 5.1 a) Read in the data and, using the trapezoidal rule, calculate from them the approximate distance traveled by the ...
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1answer
137 views

Evaluating π using Monte Carlo methods - Serial vs OMP

I wrote this simple code for evaluating the π using Monte Carlo method. This is the serial version: ...
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1answer
92 views

Continuous Fourier integrals by Ooura's method

I have a PR implementing Ooura and Mori's method for continuous Fourier integrals. I used it here to compute an oscillatory integral that Mathematica got completely wrong, and then I thought "well ...
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1answer
244 views

Parallel Ramanujan's formula for 1/π calculation

I finished my university project for calculating \$1/\pi\$ and I would love to get some feedback. Before you guys jump into this code please keep in mind newcomer to C++ just decided to use it for ...
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Numerical integration in cython

I have a set of nested functions that I need to call multiple times. I know scipy.quad is pretty fast, but I will need to call the integrator recursively and want ...
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2answers
142 views

Simple function that simulates survey results based on sample size and probability

What is this: This is a simple function, part of a basic Monte Carlo simulation. It takes sample size and probability as parameters. It returns the simulation result (positive answers) plus the input ...
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1answer
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Calculating pi via collisions

This code calculates pi via collisions; it asks for a user input of N which determines the mass of the second block. It is fully working, it just takes forever to run when N >= 2. I want to be able ...
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1answer
56 views

Monte Carlo pi animation

I have created a program that calculates pi using a Monte Carlo method. It also animates the process and displays the value as it is updated to show how it gets closer and closer to the actual value ...
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1answer
88 views

Monte Carlo errors estimation routine

I would value your opinion on the following piece of code. I am rather new to both Python and Monte Carlo analysis, so I was wondering whether the routine makes sense to more experienced and ...
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1answer
355 views

Java Pi Calculation using an Averaged-Leibniz formula

While trying to discover a way to calculate the digits of Pi faster with the Leibniz formula for Pi, I noticed that, if I took two consecuent numbers in the series, and calculate their average, I ...
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1answer
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C++ Pi Calculator - Leibniz Formula

Yesterday I saw a CodeTrain video in where Daniel Shiffman tried to approximate Pi using the Leibniz series. It was interesting so I decided to try it too. I wrote this console application with a ...
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2answers
2k views

Calculate Pi using Monte Carlo

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1answer
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A simple clusterness measure of data in one dimension using Java

Problem definition Given \$X = (x_1, \dots, x_n)\$ such that \$x_1 \leq x_2 \leq \dots \leq x_n \$. Let \$x_{\min} = \min X = x_1\$, \$x_{\max} = \max X = x_n\$ and \$r = x_{\max} - x_{\min}\$. Also, ...
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1answer
205 views

Polynomial implementation in Golang

I am writing a numerical analysis library in golang for which I need to implement a polynomial struct. Here is the source code: ...
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2answers
2k views

Simulating a two-body collision problem to find digits of Pi

I came across a nice video on 3Blue1Brown's channel that highlights a very indirect way to find the digits in Pi. I'd suggest watching the whole video, but briefly: The setup is as above. A "small" ...
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1answer
156 views

Discrete Lanczos Derivatives

I have a PR implementing denoising discrete Lanczos derivatives, following this paper. The following code works well, but the design is a train wreck, and I was hoping to get some advice to improve it....
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3answers
110 views

A collection of vector functionals

I would like some feedback for a collection of what I call "vector functionals", by which I mean maps \$\ell\colon \mathbb{K}^{n} \to \mathbb{K}\$, where the field \$\mathbb{K} = \mathbb{R}\$ or \$\...
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1answer
162 views

Complex Newton's Method

I'm trying to build a complex Newton's method. I've submitted a PR here, where you can see the documentation and tests, as well as get a compiling example. I'd appreciate y'alls help reducing the ...
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Bisection and Newton's method for finding a root of an equation

In an attempt to learn Rust, I've written up implementations of the bisection method and Newton's method for finding roots of an equation. Both methods come in two variants: the first one searches for ...
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Metropolis Monte Carlo Sampler in Rust

the following is an implementation of the standard Metropolis Hastings Monte Carlo sampler. You can read more about it here. At the end I am going to give you a link to the Rust playground, so you ...
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1answer
386 views

Verilog implementation of trapezoidal integration method

Any and all comments are welcome in this review. Problem I've been doing a lot with numerical integration methods recently and have mostly been programming in Python. But...speedups! And FPGAs are ...
7
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1answer
107 views

Implementing numerical integration in Python

I have this Python code that implements a rectangular numerical integration. It evaluates the (K-1)-dimensional integral for arbitrary integer \$K \geq 1\$ $$\int_{u_K = 0}^{\gamma}\int_{u_{K-1} = 0}^...
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3answers
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Implementing numerical integration

I have this C++ code that implements a rectangular numerical integration. It evaluates the \$K\$-dimensional integral $$\int_{u_K = 0}^{\gamma}\int_{u_{K-1} = 0}^{\gamma-u_K}\cdots\int_{u_2}^{\...
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3answers
1k views

Bisection to find roots in C++

I have written a short C/C++ code finding root by bisection. (This is a simple iterative numerical method allowing to find the root of an equation i.e. x such that f(x) = 0). Bisection Method The ...
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1answer
384 views

2d linear Partial Differential Equation Solver using finite differences

This is code that solves partial differential equations on a rectangular domain using partial differences. fd_solve takes an equation, a partially filled in output, ...
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1answer
232 views

Compute PI in Kotlin on a T-shirt

I have written code in Kotlin with the objective of computing Pi in few enough lines so that it looks good on a t-shirt. Can be cut and paste into http://try.kotlinlang.org under "My Programs" and ...