# All Questions

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37 views

### Create New Type of Layer For Neural Network

I'm doing some work exploring modelling neural networks in which each neuron could represent a different type of physical system. What I want to do is, I think, quite different to what an ordinary ...
34 views

### Problems in optimizing a function over two variables

The following function needs to be maximized over the variable $a1$ and $a2$ in the range $0 \le a1 <1$ and $0\le a2 <1$: ...
126 views

### Problem with FindFormula for experimental dataset [closed]

I have a dataset whose mathematical model is unknown. There is my code. ...
104 views

### How can I solve a Set Cover problem in Mathematica

I have $n$ non-empty possibly non-disjoint sets $S_i$, each having a cost $c_i$, and the union $\Omega=\bigcup_{i=1}^{n}S_i$. How can I find a selection of $S_i$ such that the union is also $\Omega$ ...
118 views

### How does DirichletConvolve relate to Dirichlet convolution?

Mathematica's Help documentation on DirichletConvolve is economical, to say the least. It claims the function "gives the Dirichlet convolution of the ...
82 views

### State Covid-19 cases

The aim of the function below is to take a state US s and county c and return the total number of covid-19 cases. ...
96 views

### How can I configure both Mathematica and the FrontEnd (whatever it is) to use the directory of the current notebook when saving/exporting graphics?

My system: Mathematica 11.2, Windows 10 Problem: I am (perpetually) working on my lecture notes, adding graphics produced by Mathematica. Obviously the notebooks I created for this purpose are in the ...
33 views

### Why is my dynamic slider no longer working?

This used to work but I accidentally made some unrecoverable edits and it stopped displaying. It supposed to adjust the background color of the current notebook. Please have a look and see what is ...
48 views

### Issue with Option Filling -> Axis

In mathematica 12.0, the following code ...
28 views

### How do I add the carriage return at the end each line?

I am working with SRIM. It takes as input, files each of whose lines end with the carriage return and line feed characters (respectively #13 and #10 ASCII characters) as said in the tutorial (page 15):...
120 views

### Calculate combined standard deviation

If I have a data that I fit with NonlinearModelfit that fits a data based on two fitting parameters, c1 and ...
87 views

### What are some debugging helpers or tips/tricks in your Mathematica toolbag?

I am a novice so imagine my confusion with Mathematica's very poor error and trace messages. Debugging should be an easy thing to do even for beginning programmers but not with Mathematica. What are ...
21 views

I finally have my autoSave[] function that appears to work. Although it does automatically save file the DateString (dynamic in-...
32 views

### ListPlot 3 column data file

I have a 3 column data file x,y,z. I want to plot y vs x in the plane, taking z as lateral color bar. I tried ListDensityPlot[{x, y, z} // Transpose] but did not ...
74 views

### Two-color HatchFilling

Is there an easy way to make HatchFilling use two alternating colors? E.g. ...
17 views

### How do I open and use(run) an Interactive Demonstration locally with Wolfram Player

I have multiple Macs, run a full Mathematica on one, and am trying to use the free Wolfram Player on another. Wolfram Player is installed and is version 12.1--the latest. See https://www.wolfram.com/...
35 views

### Launch PDF viewer from within a Mathematica Notebook

I would like to view a designated PDF document by clicking on a hyperlink in a Mathematica notebook. I am able to open the designated PDF document using SystemOpen["E:\OneDrive\Learning ...
56 views

### Counting real roots of bivariate polynomial

For a proof, I'm working with a polynomial $p(x,m)$ and I need to show that: For any $m\in (0,6)$, $p_m(x)\equiv p(x,m)$ has a unique real root in $(0,1/2)$. I find that this is true by using Reduce ...
46 views

### Define a Region where a disequation is satisfied for all values of a variable

I'm having a problem with Mathematica. I have a large and complicate system of 3 inequalities in 3 variables, let's call them x,y,z. Now, I can't use reduce to solve it exactly. There is a way to ...
106 views

### How to get elements corresponding to UpperTriangularize

For a generally non-square matrix M, I want the upper triangle that include the diagonal entries. Specifically, this is implemented via UpperTriangularize: ...
56 views

### How to use StreamPlot to plot the typical solution in this directional field?

How can I plot the typical solution in this directional field using StreamPlot? ...
122 views
+100

I have a working curl command: curl https://myapp.herokuapp.com/doit -F filedata=@path/to/img.jpg How do I write this in the modern way with ...
43 views

### Making Table with nested SetDelay functions is very slow

I am trying to write a function which returns a list of lists of eigenenergies available for a quantum well. The code is here: ...
55 views

### is Epidemic Data For Novel Coronavirus COVID-19 not updated?

I am trying to get the epidemic data of Colombia and I encounter that since May 27 there is not information about. The data which I obtained is ...
63 views

### Plot implicit polar equation streamlines

I'm trying to plot streamlines of Stokes solution to an sphere, the expression of streamlines is I've seen similar questions before and this what I have tried As you can see, a=1, U=1, but it seems ...
156 views

### Double summation

Can Mathematica compute a double sums such as: Sum[If[m == n == 0, 0, 1/(m^2 + n^2)^3], {m, -∞, ∞}, {n, -∞, \ ∞}] The analytic expression can be found in https:/...
42 views

### How to calculate with right probabilities values?

My code solves the equation G(Ht) using random p probabilities for each value of d in my <...
62 views

### Why are Solve and LinearSolve returning different solutions here?

I'm working on a problem which requires me to take some numerical data I have from previous work, and use the data in the construction of new equations which I then have to solve. I can set up the ...
58 views

### How to get rid of imaginary part in cubic root

When I try to solve the following cubic equation for $a$ on mathematica : S=Solve[a^3 - 4 x - 2 a^2 x + 8 x^3 + a (- 6 - 4 x^2) == 0,a]; I get a complex expression ...
17 views

### Is there a way to count quantity of evaluations (this preferred) or edits in a cell since last notebook save?

Abstract The goal is to use this to create an autoSave[evals_:5]:=Module[{}, save after set number of evaluations or edits have occured...]. I asked a similar ...
63 views

### Restrict gaussian multi-peak fitting by area

I am trying to implement the code developed by @MarcoB here: Multi-peak fitting and area of the fitting but trying to restrict the fitting of the peaks by the area, height, the width and the position, ...
233 views

### How do I convert a list to a Graph with directed edges?

I created a discrete Markov process using p = DiscreteMarkovProcess[{1, 0, 0}, {{0, 1/2, 1/2}, {1/2, 0, 1/2}, {1/2, 1/2, 0}}]; and simulated it 5 times to create a ...
39 views

### Fitting an integral function given a set of data points

I have a set of measures of the resistivity of a given material at different thicknesses and I'm trying to fit them using the Fuchs-Sondheimer model. My code is: ...
36 views

### DecompositionNDSolveValue analogue for NDEigenvalues

In FEMAddOns there is a function DecompositionNDSolveValue to solve stationary PDEs on a cluster. Is there a similar way to solve the eigenvalue problem for a system of ODEs in parallel kernels, ...
39 views

### Issues arising when using UnitSimplify for getting a dimensionless expression

I am having some difficulties when using UnitSimplify in manipulating expressions for obtaining dimensionless quantities in Mathematica 12.0.0. Here is a minimal ...
120 views

### MeshRefinementFunction analogue for ToElementMesh

MeshRefinementFunction according to the documentation is an option for DiscretizeRegion. Is there an analogue for ...
45 views

### Scan and Set over multi-dimensional data

Suppose I have the following: Table[x[i,j] = f[i,j], {i,1,10},{j,1,10}]; I want to set variables x[i,j] to have value ...
68 views

### Openning JSON file, (NDJSON, new line delimited) — big file

I am trying since many hours to open a JSON file ("new line delimited") that has this as structure ...