# All Questions

135 views

### Transcritical Bifurcation phase portraits

An example equation for a Transcritical Bifurcations is given by: $$\dfrac{dx}{dt} = f(x, r) = r x - x^2$$ In Mathematica, we can define the function as: ...
64 views

### Why does NDSolve and NIntegrate not give the same result?

I have plotted solution of two equivalent equations one in Integral form (right chart) the other in Differential form (left chart) using NDSolve and NIntegrate but they give me completely different ...
179 views

### Finding Coordinates of a Peak on a Plot

I have plotted a graph from a CSV file which consists of two columns of data Time and Intensity. I simply want to find the time where the intensity is largest. This code: ...
451 views

### Gâteaux (directional) derivatives and higher order differentials of a functional

I would like to calculate the Gâteaux derivative of a functional (i.e. a function depending on functions). A simple example for the Dirichlet functional: $L(u(x))=\int_0^1 \frac{1}{2} (u'(x))^2 dx$ ...
573 views

### Pulsed NMR animation

I'm new here and have never interacted with the community so excuse me if this has been asked before or if I format incorrectly or anything like that. Anyway, I'm trying to make an animation for a ...
193 views

### How to get exact coordinate of a point from a plot?

I am using BodePlot[] to plot the magnitude and phase of a function as below. BodePlot[1000/((1 + s/10^3)*(1 + s/10^6))] ...
2k views

### Fetching data from HTML source

I want to generate a couple of plots/graphs with Area 51 statistics. Since Area 51 doesn't work with the SE API, I'm forced to find another way to get the information I want. That other way is with ...
146 views

### Plots without axes labeling [duplicate]

I need to plot in Mathematica without labeling. For example, this code: ...
112 views

### Plot with two LabelStyle

I need to plot a graph using two different colors for the axis labels. Not working example: ...
132 views

Suppose I have a quadratic polynomial in two variables x and y in which the squares with respect to ...
103 views

### Filters on image vs data

I was using GaussianFilter and realized that applying it to an array yields a different result from applying it to an image. For instance: ...
50 views

### NDSolve returns solution with single point domain

Thanks to helpful comments from Michael E2 and George2079, I was able to focus in on exactly the source of the issue. With some simplification, I can reduce the problem to: ...
82 views

### replacement rule doesn't work

I define a function which counts the number of negative elements in a list as follows: g[x1_, x2_] := Count[{x1, x2}, _?Negative] Plugging in values shows that ...
39 views

### Testing if a character is a whitespace [on hold]

Is it possible to define a function which returns true if its only argument is a whitespace character (space, tab, newline, ecc...), false otherwise? I tried with various testing functions on the ...
64 views

### Extended AutoCorrelation Function

Is there a function in Mathematica capable of computing the sample Extended AutoCorrelation Function (EACF)? I know that there's a package in R that does this. I was trying to avoid to having to ...
725 views

### Why is Mathematica destroying this graph?

Here I have a picture of a function I graphed: reg[x_,y_]:=(x^2+y^2)Cos[4ArcTan[y/x]]; Plot3D[reg[x,y],{x,-2,2},{y,-2,2},AxesLabel->Automatic] And here is ...
35 views

### Create a loop for assignment of Solve output [duplicate]

Is there a way to automatically assign the output of solve to a number of symbols? For example, assume that I have the solve statement as follows: ...
74 views

### Get wrong coordinate in plot [on hold]

I am having problem with getting the coordinate of points on the plot below. The plot is OK but when I press Ctr + D and move cursor along the line, the coordinates are total wrong? Could you help ...
46 views

### Minimize variable domain neither real nor integer [on hold]

In Mathematica, can I have a variable domain something like x ∈ {1, 1/k}, where k is a constant? In my problem formulation ...
31 views

### Scaling HSB colors for export

In Mathematica, Hue[h,s,b] uses HSB colors. However, unlike anything I've ever seen, the h, ...
52 views

### How can use Table for two functions obtained from NDSolve? [on hold]

I have obtained a numerical solution using NDSolve for two functions a(x) and b(x). how do I use Table to make a list of a(x) vs b(x) values. is it simply Table[{a(x),b(x)},{x,0,100}] or should I use ...
30 views

### Insert several sequential alphanumeric characters pdf [on hold]

As I can make it through "this" directory 1 to "this" in the directory 2 and so on for 50 pdf, Deputy sample directory Example
129 views

### Setting ChartLabels in a histogram

I have two data sets that I use to build a histogram in the following code: ...
160 views

### Searching a phrase in all *.nb files

I have so many *.nb files in a folder. In one of them I have written a phrase, unfortunately I cannot remember that file. I am searching about it and the file in ...
118 views

### Fractal plotting for the Collatz fractal

I have the following equation: f[z_] := 1/4 (2 + 7 z - (2 + 5 z) Cos[Pi*z]) I want to map this on the imaginary plane such that if it converges under iterations ...
458 views

### Numerical instability in cosh and sinh - integral functions [duplicate]

I'm trying to calculate the function: CoshIntegral[x] Sinh[x] - Cosh[x] SinhIntegral[x] Unfortunately Mathematica seems to hit a point (x~20) and things become ...
244 views

### Strange phenomenon occurring in analytic integration result involving Bessel functions

For the following integral, Integrate[x^2 Exp[-a x^2 - b x^4], {x, -∞, ∞}, Assumptions -> {a > 0, b > 0}] Mathematica gives the following analytic ...
34 views

### Quits Kernel during evaluation of CreateTopologies

I am using Feynarts 3.9 and FeynCalc 9.0.1 with Mathematica 10. Every time I load FeynArts with FeynCalc and execute t = CreateTopologies[1, 1 -> 2]; ...
3k views

### Flatten command: matrix as second argument

One thing I could never wrap my head around is how Flatten works when provided with a matrix as the second argument, and the Mathematica help isn't particularly ...
107 views

### Quantifier elimination by using Resolve outputs a formula that is “too complicated”

The following command: ...
166 views

### Looking for a better way to delete an arbitrary list of rows from a matrix

Delete is not suitable to delete the rows of a matrix, as illustrated below: ...
3 views

### Query about hyperplane in SVM [migrated]

I am a beginner in Machine Learning. I was reading through basics of SVM and read this definition: The goal of a support vector machine is to find the optimal separating hyperplane which ...
54 views

### FindMinimum step size too small

I'm running a simulation of an electromagnetic system using Radia, an external code that is run from Mathematica. I want to use FindMinimum to determine some ...
2k views

### How best to embed various cell groups into a $\LaTeX$ project?

I'm an author and a coder. I want to reference various parts of my notebooks in my $\LaTeX$ project. I've tried doing the following, using a post on the $\LaTeX$ side of this problem. I'd like to ...
236 views

### ParametricPlot3D of Boy's surface

I'm trying to visualize Boy's surface using Bryant's parametrization, as per the MathWorld article. However, I'm not sure I understand the parametrization, and I don't know how to implement it when ...
358 views

### How to export figures with normal spacing in texts?

My OS is Ubuntu 14.04, and I use MMA 10. I export a figure ploted in MMA to a pdf file and then import the pdf in Latex, here is the sreenshot As you can see, the spacing in the text is odd. But ...
229 views

### Mathematica Interpolation or approximation

I have lists of points X and Y. {1212,1216,1217,1219...}, {1,2,3,4,5,6...} I combine ...
90 views

### UseFrontEnd is not working the same in version 10.4

I'm using batch files to run Mathematica notebooks (with saved output) but in version 10.4 the functionality has changed. Any ideas how to get it working? I use a batch file to run a .m script which ...
56 views

### Starting notebook from text mode

I am trying to start new notebook from a command line mode with command UsingFrontEnd@CreateDocument[] The notebook is created but it stays in minimized mode at the ...
62 views

### Plotting the InterpolatingFunction from NDSolve [on hold]

I want to plot the solution of a differential equation which i solve it numerically with NDSolve. Here's the code: ...
32 views

### How do you make y-axis labels and Ticks bigger in a BoxWhiskerChart

I'm trying to do a BoxWhiskerChart in Mathematica with a very specific Style. Specifically, I'm trying to get the y-axis labels (the numbers) to be bigger (point ...
32 views

### FindSpanningTree command doesn't work

I want to solve a network analysis problem by FindSpanningTree command. But it yields nothing: FindSpanningTree[G1] ...
28 views

### How can I define MakeBoxes for Inactive forms user-defined heads?

Here I define a MakeBoxes for Times: ...
54 views

### How to plot a function whose constant parameters have associated uncertainties in Mathematica 8.0?

Let's assume I want to plot the function $f(x)=a + bx+ cx^{2}$, where experimentally known values of parameters $a, b$ and, $c$ are as follows: $a=1.01 \pm 0.18$ $b=0.92 \pm 0.11$ $c=2.2 \pm 0.2$ ...
227 views

### Asymptotic forms of Bessel function

I want to replace Bessel functions by asymptotic forms, so the question is: can I find the best ones with help of Mathematica? And if it's possible, how can I do it? Update How can I get with ...
109 views

### MacDonald formula for Modified Bessel Functions

How can I make Mathematica understand these two integrals? $$\int_0^{\infty} e^{-x \cosh{\xi}} d\xi = K_0(x)$$ \int_0^{\infty} e^{-\frac{1}{2} \Big( \frac{x y}{u} + u \frac{x^2+y^2}{x y} \Big) } ...
53 views

### Inconsistent performance of code

I'm trying to do some optimizations to my code to make it run faster, but it seems that there are inconsistencies in the performance of the code. Namely, the codes have different performance in ...
74 views

### Visualize Pascal's triangle with the product of the terms in the $n$th row

How to make the following graphics by using Mathematica? What I tried: I used J.M's answer for the Pascal triangle ...