# All Questions

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### Simplification of complex number factors out an extra i

When I evaluate Simplify[ - a - I Sqrt[3] a - b - I Sqrt[3] b ] Mathematica returns -I (-I + Sqrt[3]) (a + b) Personally, I ...
1 vote
15 views

### How to create a sequence of functions defined recursively?

I'm trying to create a Table of functions where each new element is defined recursively via indefinite integration of the previous one. I've tried doing: ...
34 views

### Least norm solution to a set of linear equations [closed]

Suppose I have a set of linear equations $M x = y$ where there are infinitely many solutions. I want to find a solution $x$ with the smallest $l_2$ norm $\|x\|_2$. Is there an efficient way to do this?...
27 views

### Why is my svg image composed of surfaces instead of lines?

I'm trying to export this plot in svg format. However, if you analyze the exported svg image, you would see that they're composed of surfaces instead of lines like this: I suspect that this is the ...
85 views

### How to insert AutomaticNumbering programmatically?

Preamble: I often work with the JournalArticle Stylesheet and use in it the styles "Figure" for graphics and "FigurCaption" for the corresponding caption. The figures should be ...
61 views

### Animating a Sphere Eversion (Turning a sphere inside out)

I'm interested in animating a sphere eversion like the one shown in the following gif. The full video is here: https://www.youtube.com/watch?v=OI-To1eUtuU Normally, I would offer my own code as a ...
81 views

### RandomFunction with a QueueingProcess for more than one service handler hangs, why?

In Mathematica, I want to, say, investigate a M/M/4 queue, that is a single queue with 4 services each handling jobs from that same queue. The arrival rate is 4 and the service rate is 2. I've ...
22 views

1 vote
173 views

### How to plot the data where y is a function?

how can I plot the data (x,y)by knowing a and b and x values? x = {0.2, 11, 16}; y = Exp[(-a*x - b*x^2)]; a = {0.510, 0.280, 0.250}; b = {0.380, 0.240, 0.330};
3k views

### FEM: user material subroutines (UMAT in ABAQUS), mechanics

Just a quick question (mainly for those who are also familiar with ABAQUS or other comparable FEM programs and non-linear modelling of mechanical behavior, e.g., plasticity). Is there any module in ...
364 views

### Extract four (von Neumann) neighbors of a matrix entry

Assume I have a $m\times n$ matrix and I would like to extract four neighbors of randomly selected entry of a matrix. I have handled if location is not on the boundary. Any suggestion how to handle it ...
30 views

### Reuse same layer of Neural Network

I hope to wrap up ConvolutionLayer in a way so that it takes two inputs, does the same operation on those, and outputs their result respectively. For example, ...
140 views

### Is MeanPredictionBands synonymous with a confidence interval in Mathematica?

I am a little confused by Mathematica's use of the term prediction interval in NonlinearModelFit. We are given two kinds of prediction bands as an option: ...
232 views

### Inconsistent behaviour between Active and Inactive forms of PDEs (finite element method)

Bug introduced in 13.0 or earlier and fixed in 13.1.0 I have been using the finite element tools in Mathematica version 13.0 to solve eigenvalue problems in physics (Schrödinger equation) using ...
208 views

### Memory use buildup when solving PDE multiple times

Bug introduced in 13.0 or earlier and fixed in 13.1.0 Mathematica V 13.0 Mac OS X ARM (64-bit) - MacBook Pro 13" M1 processor macOS Big Sur 11.6.2 I am solving a PDE numerically and have noticed ...
4k views

### Future enhancements for the finite element method

How should the finite element method (FEM) framework in the language be extended to be more useful? With the release of version 12.0 all fundamental FEM solvers (linear, nonlinear, stationary, ...
34 views

### How to simplify a formula with integrations by parts?

I have a huge expression to compute, which contains lots of different terms composed of multiplication of various functions, derived a certain number of times (non derived, derived once or twice). For ...
33 views

### How to project a 2D region from one plane to another?

I have one of a general set of 2D regions (Disk, Rectangle, Polygon, etc.), as well as 3D origin points and normal vectors defining two reference planes/coordinate systems. I also have a x vector ...
195 views

### NIntegrate can't handle InterpolatingFunction produced by FiniteElement properly?

Bug introduced in 12.3.1 or earlier and fixed in 13.1.0 This is a problem comes out in the discussion here and I think it's worth posting a new question for it. Consider the following sample: ...
105 views

### Why does SolidMechanicsStrain calculated inside a module give strange results?

Bug introduced in 13.0 and fixed in 13.1.0 I am exploring the FE capabilities of Mathematica and trying a few solid mechanics problems with the aim of bringing them into my teaching. The problem is a ...
10 views

### How to measure a LearnedDistribution?

I would like to measure the qualities of a LearnedDistribution in general and with regard to test sets. The docs say that it takes an option ValidationSet, but ...
2k views

### How to simulate the true reflective movement of a particle bouncing around in an ellipse?

Please help me to simulate the movement of a particle inside a region with elliptical walls such that particle is reflected from the walls and continues to move. A friend was able write code to ...
40 views

### efficient code to search for formulas for calculating primes

I had an idea for calculating primes using smaller primes given the following: p1=(p2-p3/p4)+(p5-p6/p7) where p1>p5>p2 and p2>p3>p4 and p5>p6>p7 and p1 through p7 are all prime ...
187 views

### Convert image of roads to 3D graphics

I have images like this: and I want to convert those lines to 3D graphics so I can export it as OBJ or STL. My best attempt has been by using MorphologicalGraph (following this post) and doing: ...
191 views

### How to dilate binary image from outside-to-inside?

I have a binary image of a line, like this one: What I'd like to do is to dilate the line, but only towards the 'inside' of the line. That is, to add white pixels towards the center of the image, ...
29 views

### Plotting a table with one x-value and multiple y-values

I have a table which reads ...
25 views

### Calling Mathematica functions from Node js project. Similar to .NET by making Mathematica Kernel? [closed]

How to call Mathematica functions from my Node js project? Is there any way I can do it like we do in .NET by making mathematica kernel?
1 vote
61 views

### Create grid-like Image3D

I would like to create a visualization of a volume with the help of equally-spaced grid lines. The effect I want to get is easily obtainable for 2D images, the image is simply divided into quadratic ...
61 views

How can I add arrows for axes of frame? This works well if there is no frame but it doesn't work when I added frame. ...
1 vote
65 views

### Suggestions to simplify and perform the summation of a complicated expression

I have a very complicated expression involving Hermite polynomials of complex variables, exponential and hyperbolic functions. Since it is too long to be pasted here, you can find the expression here. ...
2k views

### Change integration variable

Are there any automated procedures to change integration variables? For example by changing Sin[u]->x, I can change ...
4k views

### How to change coordinates of integration?

Is there some built-in routine, some easier method to change variables of integration, without/before solving the integral? Say I have ...
4k views

### Is there a way to rewrite integrals in Mathematica using u substitution?

In Mathematica, can I give it an integral and a few substitution rules and have it rewrite the integral in terms of those variables?
1 vote
39 views

### Channel-Based Communication and MQTT?

it seems to me that with the Channel-Based Communication a "subscription" of a private MQTT-Channel should be possible especially Wolfram mentioned that one can commit the MQTT-Path like ...
47 views

### How can I flip/mirror the legend? [duplicate]

How can I flip/mirror the legend like this? The text should be right aligned and if the text is longer than the text move to the left. ...
1 vote
74 views

### Weird Infinite Limit results when dividing functions

I am getting 0 or 1 for the limit when dividing the two functions but Log of the same constant when taking the limit individually. ...
52 views

### How to execute Wolfram Language code/scripts in R Studio (or similar)?

How to execute the Wolfram Language in R Studio?, or similar. https://www.wolfram.com/wolframscript/?source=nav
155 views

### Solve for p of Binomial distribution

Is there a way to solve for the probability p of a binomial distribution in a set of equations? With some arbitrary functions g[ _ ] and f[ _ ] such that: ...
1 vote
25 views

### How to middle align text and the markers and place the legends for this?

How can I middle align the legends and markers? Changing the font size make it not aligned. ...
45 views

### How do I import a file only when it is modified?

I am trying to create a Dynamic code that will Import the contents of file only if it has been modified. I tried the following ...
1 vote
110 views

### Trouble when attempting to import a dat resource

I am trying to import the "Patient Medical Data for Novel Coronavirus COVID-19" dataset from the Wolfram Data Repository, but when I import, it shows me just 427036 results instead of the ...
1 vote
42 views

### How can I collect the sum of any number of gradients without using ReplaceRepeated[]?

Recently, I have run into the problem where I need to collect the the sum of any number of gradients. I have defined a function grad[] to represent the gradient, ...
148 views

### Pushing Mathematica's FullSimplify to a global complexity minimum

Original: Is there any way to control Mathematica's inner simplification algorithm? I have seen several instances where FullSimplify does not yield the most optimal ...
1 vote
59 views

### How can I calculate the diameters from the craters in this image?

I am new to Image Processing and I want to know a way to find the diameters of the craters.
39 views

### Compile and QPochhammer Function

I am running into trouble trying to make a listable function run in parallel. Arguably, the function that I am trying to compile is rather complicated. Whenever I run the code below ...
I have a $2\times 2$ symbolic matrix for which I want to compute the eigenvalues. It is given as: Clear[a, b, m] m={{a, b}, {b, -a}} and it spits out the ...