4
votes
1answer
258 views

Averaging over a circle from FFT to plot the amplitude vs wavelength

I am trying to calculate the amplitude of FFT vs wavelength for some experiments. I had put a question here previously on how to compute the FFT of an image. Thanks to everyone who provided the ...
9
votes
1answer
125 views

Union on Associations (Kernel Kill)

Bug introduced in 10.1 and fixed in 10.2.0 Perhaps Union on Associations is not being encouraged since ...
3
votes
1answer
67 views

Fourier cosine series of displacement

I'm trying to calculate a Fourier Cosine Series of displacement for general 4-bar mechanism. My code not working. I don't understand why. I need the result as this form ...
6
votes
2answers
349 views

Round vs. Floor vs. Ceiling for non-integers non-orders-of-magnitude

I understand that Round give the nearest even integer for cases where the number is between two integers, i.e. Round[2.5] = 2 ...
1
vote
5answers
162 views

Select using MemberQ

I want to make a selection on this list ...
13
votes
2answers
364 views

Why does leaving and re-entering a context lose values defined in that context?

I'm getting unexpected behavior when beginning a new context, leaving it, and then re-entering it. Specifically, when re-entering the context, symbols that had been previously defined in that context ...
1
vote
2answers
58 views

Specifying the PlotRange according to a desired center

I have this plot of $f(x)=\ln x$ and the tangent line at $x=e$, and I'd like to specify the PlotRange so that it's the rectangle with its centroid at $(e,1)$, kind ...
4
votes
0answers
96 views

Inverse of piecewise function with pieces invertible on specific domain

I have piecewise continuous function defined below: f=Piecewise[{ {15 + 1/6*(# - 3), # <= 27}, {# - 12 + 4 * Exp[-5/24*(#-27)], 27 < #} }]; This ...
2
votes
0answers
52 views

Is there a keyboard shortcut that reproduces the code two input cells above the current cursor location?

In Mathematica running on OS X, Cmnd+L is one of my favorite keyboard shortcuts, as it reproduces the code in the input cell above cursor location into the current cell or into a new cell when the ...
0
votes
1answer
70 views
-2
votes
1answer
256 views

How to get the coordinates of points within an image?

How can I get the coordinates of an image, and make Mathematica draw the image from the coordinates found? I am interested in just the outlines of the regions. Here is an example of the kinds of ...
0
votes
0answers
40 views

How to print intermediate steps of simplifying a power formula? [duplicate]

To answer the question of proving Fibonacci sequence is periodic mod 5 without using induction., I came across Mathematica to prove $$F_{n}\equiv F_{n+20}\pmod 5$$ for all $n \geq 2$ I defined: ...
1
vote
1answer
134 views

How to make an animation of circle “decaying” into two smaller circles using Manipulate? [closed]

I have defined three functions: $x[t], x_1[t],x_2[t]$. $x[t]$ describes the motion of a circle of some radius $r$ that, at some moment $t_0$ decays into two circles of radii $r_1$ and $r_2$. The ...
0
votes
2answers
80 views

Company headquarters for each cell in a spreadsheet

I have an Excel spreadsheet column with hundreds of company names on it. I need to find the address (or just city if that's easier) The operation for this is simple in wolfram alpha. i.e. typing ...
1
vote
3answers
191 views

Draw arrows around an ellipsoid

I want a thin ellipsoid-like figure with an arrow around the ellipsoid. To draw an ellipsoid I used the following code: ...
1
vote
0answers
41 views

Mathematica Workflow [duplicate]

What methods/tools/tips have you found that dramatically improved your Mathematica workflow? I have a love/hate relationship with Mathematica. It is useful no doubt, but defies my intuition at every ...
8
votes
2answers
214 views

Efficient solution for a discrete assignment problem with pairwise costs

Let's consider a simple graph with N vertices, and a corresponding set of N items. The goal of the problem is to assign every item to a vertex on the graph so that sum of a per-edge (that is ...
1
vote
2answers
106 views

Replace For-Loop to speed up code

I need to speed up this code ...
4
votes
6answers
702 views

How to smooth the noise

This is a sample data ...
0
votes
1answer
34 views

Creating a custom list [closed]

This is the first list lts1 = Table[i, {i, -1.8, 5.8, 0.1}] 1st question: In the interval between -1.8 and 5,8 how can I choose the step beforehand so as the ...
1
vote
1answer
48 views

Find element in the table

I have a table ...
1
vote
1answer
83 views

General method for extracting graphics primitives from a plot [closed]

I often have to plot experimental data that is very noisy, and sometimes I try a bit of image processing on it. For example (using a test function) I can gaussian filter it: ...
2
votes
2answers
89 views

Using FindFit for a non-trivial complex function [duplicate]

I have data set which I would like to fit to the function $\quad \quad f(r) = A\cos(kr - \pi/4 + \phi_1)\times\exp(i(-2\log(r) + \phi_2))$, where $k$ is a constant I know and $(A,\phi_1,\phi_2)$ are ...
-2
votes
1answer
59 views

Co-ordinates/ data marker in 3D plot

How to place the data marker or see the co-ordinates in below 3D plot and how to list all data points in this plot? ...
2
votes
1answer
95 views

Extract Transfer Matrix from TransferFunctionModel

I have a MIMO transfer function model, and I'd like to know how to perform arithmetic on this model. For instance, to see the difference between two systems' outputs for arbitrary inputs, I'd like to ...
2
votes
2answers
204 views
2
votes
3answers
72 views

An extra { when importing a file [closed]

I am trying to import data from a file. {k0,{a0,b0,c0},{e0,f0,g0}} {k1,{a1,b1,c1},{e1,f1,g1}} MyList = Import[file, "Data"]; But I get a list with an extra "{" ...
1
vote
1answer
156 views

DownValues when using Set and SetDelayed

It is known from several questions asked in SE that one of the basic differences between Set and SetDelayed is that the former ...
11
votes
5answers
510 views

Find all the possible ways of partitioning a list into a set of pairs of element

I have a list {x1,...,xN} where N is even, and I need to find all the possible ways to split it into pairs of elements, e.g. the ...
2
votes
1answer
202 views

Why does NDSolveValue giving crappy results?

I have been trying out mathematica 10 features, but sadly unable to use NDSolve for even simple PDE's. I am still wrestling with the problem of boundary conditions. The solution I get in the ...
1
vote
2answers
152 views

How to plot any 7 point shape in 2D i.e. star [closed]

I am new to Mathematica and I was wondering if anyone knew how to just plot simple shapes with at least 7 points minimum in 2D. What are the required steps I would need to start this? I believe I have ...
0
votes
1answer
102 views

Creating a residual histogram from discrete 3D data and function [closed]

Hi I have this data and my function on Mathematica: ...
6
votes
2answers
218 views

What's the difference between Interpolation[pts, Method -> Spline] and BSplineCurve?

Last month, I answered a question about spline interpolation,please see here Now I do the following operations ...
5
votes
2answers
198 views

Problems with ListPolarPlot

I want to plot the data that I got from measuring the angular dependency of the radiation intensity of a microwave emitter. My data: ...
8
votes
1answer
574 views

Is there any way to reveal a removable singularity in a plot? [duplicate]

Let's say we have a function $f(x)=\dfrac{2^x-2}{x-1}$. The graph of the function in Mathematica looks like this: The function in question is obviously not continuous at $x=1$, but that doesn't ...
7
votes
1answer
161 views

Optimal Binarize value for counting experiment

I am currently working on a physics experiment where I count particles. I have looked at and used a bit of code from the following sources: Cell counting from an image file and Count Elements in Image ...
2
votes
0answers
250 views

Open LabView's TDMS file?

How to open the National Instruments LabView TDMS files? Has anyone developed a library or code for easily importing these? National Instruments provide a DLL and specification for the format. There ...
3
votes
1answer
180 views

solving system of non-homogeneous advection equation using mathematica?

This question is followed up from this question How to solve a certain coupled first order PDE system Here I consider the non-homogeneous advection system \begin{equation} ...
4
votes
1answer
332 views

Using ParametricNDSolve and NMinimize to find accurate interplanetary trajectory arrival periapse radius

I have an interplanetary trajectory simulation that calculates the required velocity (using a Lambert solver) and escape angle for a spacecraft to travel from Earth to Mars. This model does not use a ...
4
votes
1answer
299 views

Can't run Bash scripts from within Mathematica 10.1

I am working on Debian 8 (Jessie) and Mathematica 10.1 (64-bit) Home Edition. I have created a script named curl_fetch.sh. It contains the line: ...
1
vote
1answer
98 views

Handle matrices and vectors with general dimension

I have a matrix of $n \times n$ dimension: $$ K - \omega^2 M = \begin{pmatrix} 2\omega_0^2 - \omega^2 & - \omega_0^2 & 0 & \cdots & 0 \\ - \omega_0^2 & 2\omega_0^2 - \omega^2 ...
0
votes
2answers
42 views

Equality of expressions containing complex numbers [closed]

I am using Mathematica to test the equivalence of symbolic expressions. I run into what appears to be a bug when I test the equivalence of expressions involving an imaginary number taken to a complex ...
4
votes
0answers
392 views

Precision and accuracy in NDSolve and NMinimize

I use NDSolve quite a lot and have noticed that setting values for AccuracyGoal and ...
7
votes
1answer
124 views

How to select a submatrix containing similar elements from a matrix? [closed]

( This question is related but does not ( fully ) answer my questions. - Finding the position of similar elements in a matrix ) I have not written code yet, I am in the design phase of code for the ...
1
vote
1answer
114 views

Discrete plots instead of parametric plots

I have a big iteration process and I want to look at the trajectories. Although if I consider ParametricPlot for this process, Mathematica connects points with lines. And for ...
14
votes
4answers
281 views

Association's Key[key] extraction different in V10.1/V10.2

V10.1: <|a -> 1|>[Key @ a] (* Missing["KeyAbsent", Key[a]]*) V10.0: <|a -> 1|>[Key @ a] (* 1 *) Bug or ...
6
votes
1answer
143 views

NMinimize Example from Wolfram Documentation Center

Here is the third example of NMinimize function from Wolfram Documentation Center at Possible Issues section. ...
11
votes
1answer
129 views

Preventing Keys from appearing in Query Output (+ the casting of Ascending/Descending operators)

One of the challenges of coming to grips with Query's on Association's and Datasets is ...
0
votes
0answers
42 views

Signage of eigenvector [duplicate]

I am comparing eigenvectors generated from mathematica to matllab. It seems signage of eigenvector generated from Mathematica is opposite from what is generated from matlab. Can anybody review and ...
0
votes
0answers
83 views

Clairaut's Theorem

Clairaut's Theorem: Suppose $f$ is defined on a disk D that contains the point $(a,b)$. If the functions $f_{xy}$ and $f_{yx}$ are both continuous on D, then $$f_{xy}(a,b)=f_{yx}(a,b).$$ Now, check ...

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