Questions tagged [numerical-value]

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

22 questions with no upvoted or accepted answers
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257 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 <...
506 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 "...
171 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 ...
98 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 ...
55 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 ...
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 ...
40 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,\...
39 views

Finding zero linear combinations of polynomials (numerically)

I have two functions of real variables defined on two compact spaces ...
78 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 ...
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. ...
53 views

How I can plot Vector3DPlot?

I want to reproduce the vector 3D plots as shown in the figure. It's in spherical polar coordinates (i.e. vector 3D plot on plane). The angle [Theta] is spherical coordinate is determined by the ...
22 views

Dealing with small values inside numerically computed determinants

I'm working with a system that is sensitive to small changes in the parameters and it appears I found an oddity when calculating these determinants. Consider the following notebook that symbolically ...
40 views

How to time shift x-axis in mathematica simulation?

I have a simulation from a system of equations that runs from 0 to 50 Normal = NDSolve[{A /. Parameter, A == .1}, {A[t]}, {t, 0, 50}]; That produces: Now ...
82 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 ...
59 views

Integrate a multivariate function similar to a delta function

I am doing a code in Mathematica. I have the following function: ...
82 views

Change of variables in integral is not working

Consider the matrix ...
39 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:...
60 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 <...
135 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 ...
111 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. ...