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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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Efficient data structure for best-match lookup

I'm terribly sorry if this has been asked before, I searched about 30 minutes before deciding to post this and didn't find anything. I have an array of ascending numbers with no precise stepping: 12.34, 103.223, 105.3, 110, 234.45, 329.11 ... I get…
thwd
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How to use CLN : Class Library for Numbers

I need to do numerical calculations with high precision. There is a c++ library which is called "CLN",although i installed this package , but i do not know how to use it. Is there an example program which shows how to use it? Thanks
MOON
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Sorting results in a sql query alphabetically and numerically

I want to make a SELECT from a certain table (ex. "table1") with a column (ex. "column1") which contains a letter followed by a number (ex. z98, k87, a245, a241, d7, e91, e32, b212, r101, r32) Is there a way to make a select that sorts the results…
Alex
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Mathematica integrating over set of points to get analytical form of function

I have a following problem - I need to integrate such a function in Mathematica (I couldn't post an image, so I am writing it in latex form): G(r)= \int_{0}^{\infty} dq f(q)*q*sin(qr)/r To obtain function G(r) dependable on r. Nevertheless I…
John Dean
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algorithm for sorting string number in php

I want to write a program that take string numeric as input(eg,one,two,three etc) and output will be sorted by ascending order or descending order of that string and show it in string as given in…
Arbab Khan
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Numerical on Distance Vector Algorithm

I was solving an assignment on routing protocols and the following question came up. I am unable to come up with the solution. Please help. A network of 4 routers A, B, C and D is arranged like this: A_____B_____C_____D 3 2 1 The…
kshikhar
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Sort a python list of strings with a numeric number

I have a list of filenames called filelist In []: filelist Out []: ['C:\\Mon20412\\P-2NODE-RAID6-1BLACK-32k-100-segmented.xlsx', 'C:\\Mon25312\\P-2NODE-RAID6-13RED-32k-100-segmented.xlsx', …
jfran
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Methods for Linear system solution with matlab

I have a linear system Ax = b , which is created by natural splines and looks like this: where The code in matlab which is supposed to solve the system is the following: clear; clc; x = [...] ; a = [...]; x0 = ...; n = length(x) - 1 ;…
Alice1nw0
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Invalid operands to binary expression ('double(*)(double' and 'double')

I was trying to figure out the Newton's method to find the root of equation. And this bug came out and I couldn't handle it. double fn(double n){ return sin(n)+log(n)-1; } double f1n(double n){ return cos(n)+1/n; } double operation(double…
Hao Xu
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Integration of numerical data

I'm writing a test tomorrow and I'm contemplating doing everything on Matlab, to save time. Some questions require numerical integration of datapoints (points, not necessarily functions). E.g. C=[0 1 5 8 10 8 6 4 3 2.2 1.5 0.6 0]; I've used…
Mierzen
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Why am I receiving the error that I am multiplying by non-int type 'float'?

I am having problems with my code which is a Runge Kutta algorithm to numerically solve for a harmonic oscillator. Unfortunately, I am receiving an error that says I can't multiply sequence by non-int of type float. Considering this code is nearly…
user3461947
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php: Reordering an array and its subkeys

i am basically trying to make a leaderboard system. I need to put 2 types of data in my .yml file: the name of the player, and their score. Here is a var dump: array(3) { [0]=> array(2) { [0]=> string(10) "samueljh1_" …
Samueljh1
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Python sort dictionary keys by letters and then numbers

Say I have a dictionary like this, d = {"John1" : "blah blah", "John2" : "blah blah", "John11" : "blah blah", "Dave1" : "blah blah", "Dave2" : "blah blah", "Dave13" : "blah blah", "Dave23" : "blah blah"} If want to be able to sort this so it is d =…
user2909250
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Error of midpoint, trapezoidal and simpson rule in matlab

I'm writing a script to numerically find the integral using these three methods. Right now I can compute the right value for the integral, but I need also to print the error and the upper analytical bound of it. I have no idea how to do that in…
user3450025
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vb.net numericupdown empty value

i am use vb.net to make an application how i delete numeric up down value after select value from it when i try this code i receive error (Conversion from string "" to type 'Decimal' is not valid.) Public Class FormAdd Private Sub…
user3319402
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