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Questions tagged [numerical]

This tag is for questions concerning problems using numbers which either cannot be exactly solved, or where the exact solution may be much more difficult to acquire than by using numerical methods.

This tag is for questions concerning problems using numbers which either cannot be exactly solved, or where the exact solution may be much more difficult to acquire than by using numerical methods.

It includes questions about algorithms, precision and accuracy of underlying numbers, advantages and disadvantages of several methods, error propagation, problems with the underlying numbers and data structures.

508 questions
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Numerical Format in SortedDictionary

I want to store large strings converted to decimals in a SortedDictionary (as the key) but they must fit a certain format...Due to the nature of sorting strings, they will not be placed correctly as a decimal would. Here are some examples: Public…
Alex
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Calculating an integral of two numerical solutions of an ode

I would like to calculate an integral, which is determined by two functions: I(T) = ∫0T i( f(t), g(t)) dt where f and g solves ordinary differential equations and i is known. The obvious approach would be to derive a differential equation for I and…
S. Gammelmark
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Solving a non-polynomial equation numerically

I've got a problem with my equation that I try to solve numerically using both MATLAB and Symbolic Toolbox. I'm after several source pages of MATLAB help, picked up a few tricks and tried most of them, still without satisfying result. My goal is to…
Krystian Meresiński
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PYGAME - Edit colours of an image (makes white red at 255,0,0) without numerical python?

I'm making a simple game, whereby I want my characters quite customizable. I want my characters to be able to be fully edited in colours, for example, if a player wants their character to have cyan skin, they just put into the sliders, or what I…
Bluetiger6001
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Uitableview sort numerically

Long story short, I have begun working with uitableview a not long ago. I finally got everything down except for proper sorting. I can sort ascending and descending but not numerically I have been told that I need to use nsdictionary or nsnumber and…
user2093591
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What is the range for Arabic-Indic Digits (Hindu–Arabic) numeral utf8 from 0 to 9

What is the range for Arabic-Indic Digits (Hindu–Arabic) numeral utf8 from 0 to 9 for the use in regular expressions: to use in regex.
Waqleh
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How to get numerical value (PHP/Wordpress)

I don't know why but I can't get any numerical value from the following code. $key_1_value = get_post_meta($post->ID, 'Begin', true); $Begin = do_shortcode('[countup date='.$key_1_value.'][timer][/countup]'); $Nombre = intval($Begin); …
Mathieu
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segmentation fault 11 in mac, but not in linux, gcc compiler

I have a code which uses standard routines of numerical recipes for finding eigen vectors of a 3x3 matrix. While the code runs perfectly on linux machines, it fails with a segmentation fault 11 on mac. With gdb, when I back tracked I find…
Sumesh P.T
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Creating a numerical variable order

I have a set of data with 3 columns: index column (with no name), colour, colour of seed, and germination time. How do I create a numerical variable called 'order' with values 1 to 22 (the number of data sets)?
math11
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What are some (recommended) resources/book on learning C++ coding for efficient/performant math routines?

I would like to start learning and understanding what and when to optimize in a code meant for real time simulations (especially for games). There are various code snippets out there, most comparing standard trig or sqrt functions to their optimized…
teodron
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is it possible to use COLT with large matrices?

I started using COLT at some point, and now my code is using a lot of its functionality. I now need to be able to handle large sparse tensors or matrices. The tensors are very sparse, but their dimensions can be quite large. It seems like I can't…
kloop
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How to make this algorithm stable

I have to compute the iterative version of this formula: f(i)=integral ( x^i/(4x+1) ) from 0 to 1 Using these formulas: f(0)=ln(5)/4; f(i)=1/(i+1) - 4*f(i+1); I have tried tried the following: I calculate integral ( x^100/(4x+1) ) from 0 to 1,…
Ramy Al Zuhouri
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Force different characters at different positions

I'm currently working on a project in which I need to fetch street/city details from a DB using a zipcode. Dutch zipcodes use a "1111 AA" format, I would like to have this entered in a single input field while forcing the first four characters to be…
Kevin Consen
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Python 3 - Issue with filtering numerical input

I'm trying to control input to allow only greater than 0 numbers, but upon testing this block of text, if I enter an illegal character first (a string, 0 or negative number), receive the error output and then input a valid value, it returns the…
Sparx
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solve for a parameter such that area under curve equals 1

I have just found that I can use the function trapz in Matlab to find the area under a curve given a vector. What I want to do is to normalize the values in this vector in such that the area under the curve equals 1. let's say that x is a single…
mhmhsh
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