Questions tagged [numerical-value]

Question relating numerical representations, operations and methods, including approximate results instead of exact symbolic results.

21 questions with no upvoted or accepted answers
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233 views

How does NSolve find the roots to an equation?

I'm using NSolve to find the roots to a transcendental equation. For this, I need to specify a bounded region where roots are searched. What I want to know is how <...
4
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1answer
497 views

Recognize physical constants?

Is there some way to ask Mathematica to recognize physical constants, such as 32 or 9.81 (gravitational acceleration, in different units, at Earth's surface)? I have in mind something like the "...
3
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0answers
168 views

On Ж, and the fine-structure constant

I'm trying to reproduce the results from a certain infamous paper that has been moving around the web for the last few days. The details are irrelevant. This paper claims to have a closed-form ...
2
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0answers
95 views

How solve this equation and plot the results?

I want to solve the following function and get values for $\omega$. $$\omega - \omega_{21} + i/\tau_{2} - s_{1}\alpha_{1}(\omega)[1+f(\omega)] = 0$$ The function $f(\omega)$ is the troublesome ...
2
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0answers
54 views

How to convert a dollar fraction into a normal dollar amount

I'm trying to use Mathematica to compute compounded interest. I used Wolfram Alpha, and it gave me the code ...
2
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0answers
51 views

Differences in AbsoluteTiming for similar codes

Consider the two following codes with the same SeedRandom (which ensures the same set of random numbers) but different use of the ...
1
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0answers
39 views

Exponential distribution and numerical errors?

I am working on the measure of a Curie Weiss model over a lattice $$ \mu[m] = \frac{e^{\beta N (hm + m^2)}}{\sum_z e^{\beta N (hz + z^2)}}\binom{N}{\frac{(1-m)N}{2}}2^{-N} $$ where $m\in\{-1,-1+2/N,\...
1
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0answers
24 views

Getting values of EllipticK with arguments that are very near 1

I need to evaluate EllipticK[m] very close to 1. However, when I get too close to 1 the function defaults to the exact solution for 1 , which is ...
1
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0answers
38 views

Finding zero linear combinations of polynomials (numerically)

I have two functions of real variables defined on two compact spaces ...
1
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0answers
77 views

Plotting the Full width at half maximum as a function of a parameter

I have this function and I want to plot the FWHM of it as a function of the parameter "a", defined between 0 and 10. It should look like the picture attached. I also put the original equation in case ...
1
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0answers
103 views

Using Classifier with NearestNeighbors methods

I am using a Machine learning toolbox on mathematica. I have 8 classes. Training data: for each class, there 100 samples with size 160. I used this code. ...
0
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1answer
28 views

Evaluation functions with lower and upper limit ODE?

How do I find the numerical value of y at 0 and also at 1. Here is my code. I appreciate any help. ...
0
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0answers
67 views

Clebsch Gordan coefficients

I'm trying to compute various sums which contain some CG coefficients, where the sum runs over the indexes m1,m2,m corresponding to each of the three angular momenta j1,j2,j. The thing is that when I ...
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0answers
59 views

Integrate a multivariate function similar to a delta function

I am doing a code in Mathematica. I have the following function: ...
0
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0answers
81 views

Change of variables in integral is not working

Consider the matrix ...
0
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0answers
37 views

Error caused by ThreeJSymbol

I do not understand what causes non-physical answer in my code although I have read about the error. I am also getting the following error, how could I fix the example error: "CompiledFunction::cfte:...
0
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0answers
59 views

Evaluating expression with machine arithmetic gives wrong answer but evaluating with arbitrary precision works

I need to understand how Mathematica approximates symbolic numbers. I have an awful symbolic number to compute. When I do N[variable] Mathematica gives me <...
0
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0answers
129 views

Limit of a List

Is it possible to take the limit of a list instead of using the Limit method? I'll try to explain what I mean. I am generating a list of numbers that converge to some number. The generated numbers ...
0
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0answers
109 views

Problem with FindRoot + NDSolve + InterpolatingFunctionDomain

I'm trying to find the root (po) of a complicated problem (where s is a parameter): First, I need to define some functions, which involve numerically solving a differential equation. ...
0
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0answers
83 views

Maintaining working precision in my program

I am badly stuck with this program I am writing. I want output of program below to be precise up to 25 digits after decimal point. I am supplying all inputs with precision 25. But after each iteration ...
0
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0answers
156 views

Speed up numerical optimization (for plotting and solving)?

Briefly speaking, I want to plot a function PIfun[], which its value is based on numerical optimization using NMaximize. It ...