3
votes
1answer
206 views

FindFit with parameters which are simultaneously in initial conditions

I have RLC circuit. I would like to find R and L by using FindFit, but L is in initial condition and I have problem with it. Could you help me ? ...
0
votes
0answers
14 views

Numerical derivative step size

I am trying to perform a numerical derivative of some function using 'ND'. I want to know if there is a way to set the step size of differentiation to the specific value I want. Can this be done ...
2
votes
0answers
42 views

How to define Goodstein's sequence?

There is an amazing and counterintuitive theorem: For all $n$, there exists a $k$ such that the $k$-th term of the Goodstein sequence $G_k(n)=0$. In other words, every Goodstein sequence ...
-1
votes
1answer
118 views

ParametricPlot3D won't show [closed]

I want to see the image of a tube made from a space curve. I define the surface using Frenet-Serret frame but the software does not show me the plot. What might be wrong with my code? Thank you.
8
votes
1answer
239 views

Law of Cosines to determine angle change along spiral

The Spiral I'm trying to place circles along the outside of an Archimedean spiral. Shown below: ...
9
votes
2answers
309 views

WordData for other languages

Mathematica already includes dictionaries for a lot of languages. What I am looking for is a handy semantic/grammatic database for Hungarian, just like WordData for ...
1
vote
1answer
961 views

List all financial Assets data conditionally

I would like to get all the Financial Data that Mathematica respecting those constraints : The assets for which there are at least 20 years of daily price quotations. Or that have s price for each ...
2
votes
1answer
64 views

How to create a Text with certain size given in a specified way?

I have some text and I would like to show them in some order in Graphics, but I want them to be in certain size so it will looks good. (Primarily for improving my ...
2
votes
1answer
22 views

Loss of scale factor when reading/recording/rereading data in a WAV file

I use recorded data from an acquisition system in a wav file containing 6 channels, all data are encoded with 2 bytes in Integer 16. I can Import the *.wav data file and get all data in a Sound object ...
4
votes
0answers
29 views

Evaluating summations involving Fibonacci numbers in terms of Fibonacci numbers

There are many summations involving Fibonacci numbers which Mathematica 10.4 is able to evaluate directly in terms of Fibonacci numbers. For example, Mathematica evaluates the summation given below as ...
8
votes
3answers
1k views

Plotting a 2D shape along a 3D parametric function curve

Say I have a 3D curve that is parametrically defined. How would I be able to plot shapes like figure 8's whose centers are aligned along the 3D curve? Say the curve was: ...
3
votes
2answers
118 views

Creating a tube with custom caps

I need a tube with only one end capped. I can do this relatively easily with: ...
1
vote
1answer
52 views

Deleting circular regions from a larger Circle

I am trying to determine how the Dirichlet eigenvalues of the Laplacian of a circular region change. I would calculate the principal eigenvaluen of this image, and gradually decrease the radius of the ...
14
votes
3answers
1k views

Mathematica style guide?

I encountered this site today https://code.google.com/p/google-styleguide/ regarding the programming style in some languages. What would be best programming practices in Mathematica, for small and ...
7
votes
0answers
374 views
+100

How to produce the ILU0 or ILUT as stand-alone procedures on sparse matrices?

Mathematica uses the ILU0 procedures automatically to precondition large sparse linear systems; e.g. ...
0
votes
1answer
21 views

Implementing four-fermions operators on FeynRules and FeynArts

I am trying to implement operators of the form $$ \bar{q}_L \gamma^\mu T^A q_L \bar{q}_L \gamma_\mu T^A q_L $$ where T^A are the SU(3) generators and $q_L$ is the Electroweak SU(2) doublet. I use ...
2
votes
1answer
137 views

How to generate specific function using BSpline command?

I want to generate an approximation function that fits a curve to points. My goal is to obtain an actual formula. Is this possible with BSplineFunction? Using the ...
-2
votes
0answers
34 views

resetting keys after using GroupBy to total

I think I saw a question like this on the site some time ago, but can't find it. I'm using GroupBy on a list of Associations to ...
1
vote
2answers
65 views

Treating the output of a plot function as a graphics object, changing the opacity

I want to treat the output of a plot (DensityPlot specifically) as a single graphics object and reduce its opacity. Something like: ...
2
votes
2answers
313 views

Simplify results further

I have an extremely long result in polynomial form following some matrix operations. However, given the symmetry of the problem, I can safely say that the solution will reduce much further than is ...
0
votes
1answer
26 views

ListVectorPlot contour lines

I dont know why so many plot functions lack the option to display contour lines (judging by the search result for [plot function] contour lines) but ListVectorPlot is among them. If I have an array <...
0
votes
0answers
27 views

How do i get a step by step solution about aan inverse z transform ? [on hold]

Good afternoon I'd like to know how do i get the step by step solution of those types of exercises.
3
votes
1answer
232 views

Solve a nonlinear PDE equation with a Neumann boundary condition

I am trying to use Mathematica 10 to solve a PDE $$u_t=u_{xx}+u_{yy}+u(1-u),$$ in the unit disk $(x,y) \in D=\{(x,y):x^2+y^2<1\}$, with the Neumann boundary condtion $$\frac{\partial u}{\partial n}...
0
votes
1answer
27 views

Set a minimum threshold value for a function

I have defined the following function in Mathematica al[z_] := (a/((1 + a*(b/(2 Pi))*Log[z/Mz]))) (a and ...
0
votes
0answers
18 views

`{Protected, ReadProtected}` System symbols give “Set::write: ”Tag * in *[v_] is Protected" on first try

Run Quit, then Unprotect@AbelianGroup; AbelianGroup[v_] = 0; Protect@AbelianGroup; where instead of ...
-1
votes
2answers
161 views

Selecting points inside a closed curve

Let's create a rather dense grid of initial conditions ...
4
votes
1answer
109 views

Mathematica 10 enables discrete GPU

When the kernel is running, the discrete GPU is enabled automatically and battery life plummets, even though my code uses no CUDA or OpenCL functions. Is it possible to prevent that from happening? ...
2
votes
2answers
164 views

More issues Integrate, NIntegrate, FindRoot

I'm trying to solve a system of 3 non-linear equations using FindRoot and Integrate. If I start FindRoot[] close to the right answer, it works well but returns a bunch of error messages first. ...
29
votes
4answers
1k views

Filtering beat-to-beat heart rate data

From an experiment, I have a dataset of beat-to-beat heart rate data: a list of the time between each heart beat in [ms]. The data is measured using an infrared optic sensor at the finger tip. The ...
5
votes
1answer
34 views

What is the default Lighting in 3D graphics?

The default value of the Lighting. This typically uses "Standard", with several coloured lights, or ...
1
vote
1answer
49 views

Unexpected behavior of DiscretizeGraphics

As this code,we can visualize the "Test text" Graphics[Text[Style["Test text",20],{0,0}],Axes->True,AxesOrigin->{0,0}] I try to use ...
0
votes
1answer
21 views

Multivariate integration of a compicated expression

I have an expression in multiple variables that is something like ...
0
votes
0answers
30 views

Table giving error Part::pkspec1: [on hold]

I am evaluating the following expression: ...
5
votes
2answers
88 views

Inflection point and curvature

Through a coordinates list and then interpolating them I got a $f[x]$. ...
1
vote
1answer
33 views

Visualization of tracks of objects in images by superposition

I have sets of images (each contains about 3000 images where many objects are seen, each image is 4 Megapixels large, format is 8bit, gray scale, png). To get an impression about the trajectories of ...
11
votes
1answer
240 views

Gillespie Stochastic Simulation Algorithm

The Gillespie SSA is a Monte Carlo stochastic simulation algorithm to find the trajectory a dynamic system described by a reaction (or interaction) network, e.g. chemical reactions or ecological ...
-1
votes
0answers
59 views

About changing the values of global parameters within a function [on hold]

For the code below: a = 1; b = 2; f[c_, d_] =: Module[{e, f, g, h, ...}, ...]; I have references to a and ...
1
vote
1answer
105 views

How to remove parts of an expression [on hold]

I have an expression where terms Transpose[R].R appear. R is a matrix with the property Transpose[R].R=IdentityMatrix[3]. How ...
1
vote
2answers
42 views

Chains of approximate numeric equalities

Mathematica considers two numbers equal if "at most their last seven binary digits" differ. For example: ...
0
votes
0answers
21 views

Using the `TwoAxisListPlot` Package and `Show` Together

I am using the TwoAxisListPlot package to generate a plot with two y-axes (obviously!). I have made a NonlinearModelFit to one ...
-4
votes
0answers
26 views

How to open and use the blackbody radiation program in Mathematica [on hold]

I am trying to open and plot the blackbody profiles for four different temperatures which are (2000,1000,400,100)K. The y coord runs from 10^-4 to 10^6 and the x coordinate runs from 10^-10 to 10^-4. ...
3
votes
1answer
112 views

Deleting vertices from Graph and preserving Structure?

My goal is to remove vertices from graphs (and the edges from them) and then take GraphComplement to find out cut sets in graphs with sink and source such as here. So How can I delete vertices from a ...
0
votes
0answers
11 views

plotting quaternary [duplicate]

For more information to draw tetrahedron like figure for my data i again insert my data. I have 4 sets of data in 4 axis (x1,x2,x3,y) x1=0.0557 0.0575 0.0613 0.0656 0.0615 0.0448 0.0488 0.0595 0.0654 ...
0
votes
0answers
28 views

Multivariable non-linear fitting

I have a function called "C" that I know it depends on 6 variable. I have a set of data points, 6 rows by 9 columns, in which in each row only one variable is changing and the rest of the variables ...
1
vote
1answer
106 views

To deal with infinity in NDSolve

Edit: I modify the question so that it uses exactly the same expressions I am having difficulties. I just started to learn to use Mathematica, and was trying to obtain an inverse function. Helpful ...
2
votes
0answers
72 views

Bug in the “PrincipalValue” method of NIntegrate?

Update As pointed by Emilio Pisanty, one should pay attention to EvaluationMonitor to monitor principal value integration. I update the codes, and find some more ...
1
vote
1answer
45 views

How to set UnitSystem permanently

I would like to set the system of units ($UnitSystem) permanently to "Metric". I know that I can do ...
11
votes
1answer
1k views

1D Euler equations (fluid dynamics) with NDSolve

Is it possible to accurately solve the 1D Euler equations in Mathematica using NDSolve? For example, let us consider the problem given here: http://www.csun.edu/~...
5
votes
1answer
84 views

TreeForm outputs different results for the same inputs but why?

First of all, please look at the below inputs and outputs: ...
5
votes
1answer
66 views

Query or MapAt ragged associations or ignoring Missing values

Related to this question, can functions be mapped to named Keys in ragged lists of Associations? ...

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