All Questions

1
vote
1answer
32 views

Dynamic not updating InputField

I'm trying to do some interactive fitting of data using an arbitrary number of the same function (a Gaussian in this case). This means that I also have an arbitrary number of variables and constraints....
0
votes
0answers
17 views

Use FindMaxValue[f[x], x] and get value of x at the maximum [closed]

I want to obtain the maximum value of a function (say f[x]), but also the value of x for which the function is a maximum. Is ...
4
votes
3answers
164 views

Finding the index of an element to be inserted in a sorted list

I have a sorted list with no duplicates: L = {1, 2, 5, 7, 8} Given an integer n, I want to find the index of ...
0
votes
0answers
61 views

What does D mean? [closed]

I am using Wolfram Cloud for do my homework. I got the following result from a matrix multiplication. ...
0
votes
1answer
61 views

Problems with manipulation

I am plotting geodesics on an ellipsoid. My problem is that I cannot do the manipulation, from a, b, c. From the starting point and the initial vector, the manipulation works well, but from the ...
1
vote
1answer
60 views

ListPlot3D of the results of FindRoot

I have a system of 2 simultaneous equations where i want to calculate the values of Tc and Tc which ranging with the values of two variables which are wfc and V. I tried to evaluate it by using ...
0
votes
0answers
62 views

Limiting solution space for symbolic algebra problems

I have a system of 12 quadratic equations with 12 variables (x11, x12, x21, x22, x23, x33, p1, p2, p3, ϕ, μ, τ) and several positive constants,w, q1, q2. ... > 0<...
2
votes
2answers
68 views

Vortex motion equation for flux-flow instability

I am solving the motion equation of an isolated vortex oscillation in a superconductor. I am assuming that the driving force is generated by an RF current oscillating at 1.3 GHz. The main point of ...
0
votes
0answers
41 views

Testing if a function input is an integer

I am wondering why code like digitback[n_Integer] := Framed[Reverse[IntegerDigits[n]]] can check if the input for the function is an integer (this is the ...
0
votes
1answer
73 views

Modelling a cylinder

I am fairly new to Mathematica. I am trying to model an ideal cylinder of uniform density of radius R (any arbitrary value) which has a cylinder of radius R/2 missing from it. The resulting solid is ...
0
votes
1answer
29 views

Problems with creating a matrix with functions

I have a function which gives me all the coordinates of a certain bloc in a lattice (with the help of another function for rows and columns): ...
1
vote
2answers
30 views

Different styles for different points in ComplexListPlot?

I'd like to use ComplexListPlot to show a point and its image under a complex function, with the point and image having different styles, say different colors. Use,...
0
votes
1answer
27 views
6
votes
0answers
90 views

Problem with my user name

I'm trying to use the new website ("Wolfram Function Repository") and i get the following error: ...
0
votes
1answer
26 views

ListPlot3D for optimization with varying parameter values

This is a followup question from Alex Trounev's answer to my question in the following post: 3D-Plot optimization results for varying parameter values Consider my objective function, objF: ...
4
votes
1answer
54 views

Converting Daily Time Series Data into Low Frequency Data (Weekly, Bi-weekly, Monthly,..)

I have daily time series example data as follows: ...
0
votes
0answers
17 views

How to enhance the precision of the numerical solutions of ODE

Given an ODE $$D f=0$$ over the interval $[x_0,x_1] \subset \mathbb{R}$, where $D$ is a linear differential operator. I can compute the boundary condition $f(x_0)$ to a very high precision, as high as ...
7
votes
1answer
99 views
+100

NetTrain Freezes Computer

I have a neural network I am trying to train: ...
3
votes
4answers
169 views

Certain list transform

I imported three lists ...
1
vote
0answers
38 views

Fitting a Curie-Weiss law function with a diverging point to a data

I would like to fit a function to some experimental data such that the extracted value of Curie temperature (Tc) describes the temperature at which the response flattens out to a constant value. ...
0
votes
1answer
30 views

How to plot weighted sum of functions?

Consider a series of functions like Table[Cos[k t], {k, 1, 2, 1/10}] which are summed up together with some weights ...
1
vote
1answer
49 views

How to fit a list of points to a certain form given error bands?

I am trying to fit a list of points to the form F[0]/(1 - a*q^2 + b*q^4), where F[0] is the value at zero of a function, which ...
0
votes
1answer
40 views

How to work properly with assumptions?

I'm trying to find an analytical solution which depends only of $i,j$ and $a$ variables, for a serie considering some initial assumptions. The series is $$s_{i0}=s_{0j} = 1,\\ s_{11} = 1-a,\\ s_{12} ...
4
votes
1answer
43 views

Creating and Plotting a Confusion Matrix from a Plain Matrix

Using ClassifierMeasurementsObject you can plot nice ConfusionMatrix: But how to mimic this matrix plot from a plain Matrix? In other terms, from ...
0
votes
0answers
16 views

How to delpoy an APIFunction that contains an AskFunction?

I am trying to deploy on Wolfram public cloud a AskFuntion wrapped around a APIFunction. The inner AskFunction generates a conversational interface that depends on values passed by the outer ...
0
votes
2answers
62 views

How to get eigenvectors of a 4x4 matrix? [closed]

MatrixForm[m = {{2, 9, 0}, {3, 8, 9}, {3, 9, 1}}] Eigensystem[m] I am facing problem in finding eigenvectors using ...
0
votes
0answers
20 views

Problem with integrating special function under assumption

i found different results when integrating a special function (see below), depending where i place my assumption (x > 0, x0 > 0). The problem is that the two solutions are not compatible. In fact, if ...
0
votes
0answers
12 views

PopupMenu seems to have stopped working after upgrading Mathematica

I have several files with popupmenus and they seem not to work since updating Mathematica to 12.0 Is there something I should do?
10
votes
3answers
512 views

Optimising subdiagonal shift matrix generation time

I want a square matrix $A$ such that $$A_{i,i-1} = 1 \ \forall i\\ A_{i,j} = 0 \text{ for } \ j \ne i-1$$ I have tried ...
3
votes
1answer
64 views

Mathematica cannot compile complex-valued interpolated PDE coefficients? (NDSolve, Finite Elements)

Bug introduced in 11.1 or earlier, fixed in 11.3 or earlier. The following PDE pde = I Cos[x y] D[u[x, y], x] + Laplacian[u[x, y], {x, y}] == 0; Is happily ...
-1
votes
0answers
40 views

How to creating a model for prediction disease based on patients symptoms using SVM algorithm [duplicate]

I have a matrix for diseases associated with their symptoms, the columns represent symptoms each row is a disease. the labels 1 and 0 in the matrix data sets represent when a disease_i related to a ...
-1
votes
0answers
35 views

Сontour integral [migrated]

everyone. Can you help with the task?
1
vote
2answers
100 views

Error messages for FindRoot and NIntegrate

I want to solve the following problem. First, the setup. A function $V(\varphi)$ defined as \begin{multline} V(\varphi)=\frac{\alpha-3}{4}e^{\sqrt{2\alpha}\varphi}+\frac{\alpha-5} {\gamma}e^{(\...
3
votes
1answer
77 views

Structural Breaks in a Time Series Model

The Chow test is a test of whether the true coefficients in two linear regressions on different data sets are equal. In econometrics, Chow test is most commonly used in time series analysis to test ...
1
vote
1answer
40 views

Unexpected behavior from Inner[]

Does anyone know why Inner[] behaves differently in the last of these three examples? Inner[f, {a, b}, {e1, e2}, List] ...
0
votes
1answer
74 views

How can I plot a sphere like the picture in Mathematica?

The coordinate of two points are (0,0,1/3) and (0,0,-1/3) respectively.How can I get this picture in Mathematica?
1
vote
1answer
37 views

How to use CTensor for the Maxwell stress tensor F?

I have used the CTensor to compute an equation of motion. Everything is ok but the stress tensor F. How can I rewrite this tensor using CTensor. The needed ...
1
vote
2answers
33 views

NSolve cannot find solution to system of trig equations

I was making a program to convert a rotation matrix to a set of euler angles. I wanted to do this for any valid rotation order that the euler angles were made with, and I did not want to do it the ...
1
vote
1answer
24 views

How to optimize bin counts with weighted data using multiple lists?

I am trying to sort elements in multiple lists into buckets with weighted data. I can do the single-list case based on a previous question. Specifically, the code under Update in the first answer. <...
0
votes
1answer
58 views

Five equations to solve 6-variables question, is it possible?

I was given a task to find the value of variable a,b,c,d,e and f. But I'm not sure it is even possible, given that only 5 equations are available. Can anybody point out how to solve these: ...
0
votes
0answers
21 views

Two coordinate rotations and a translation to for a 4x4 matrix

I am looking to do ewo coordinate rotations and a translation. I'd like the new coordinate system to be shifted by x,y,z (in the directions of the same name) and then rotated by theta in the x hat ...
1
vote
2answers
45 views

I need the product of two functions be understood as a function itself (a Dirac delta example):

Define: In:= Dirac /: Dirac[x_, y_] f_[x_] := f[y] This works like Dirac's Delta. For example, In:= h[x] Dirac[x,y] Out:= h[y] perfect! However if I ask: In:= h[x] k[x] Dirac[x,y] Out:= h[y] ...
0
votes
0answers
19 views

CompiledFunction::ctfa - Argument should be a rank 4 tensor of machine-size real number

Dear Mathematica community, I got the following error line: CompiledFunction::ctfa "Argument {<<1>>} at position 1 should be a rank 4 tensor of machine-size real number" This is my function:...
1
vote
1answer
42 views

Variation of the biharmonic equation with Neumann conditions

I am currently writing a script to plot the solution of a variant of the biharmonic equation. In this case the equation I want to solve is ...
3
votes
2answers
99 views

Plot vectors as sums of vectors along the axes

in a phase diagram appear vectors that go in different directions. When graphing with the "streamplot" or "vectorplot" command, only the arrows appear showing how they move away from or closer to ...
0
votes
1answer
58 views

Still having problem with solving high polynomials with exponential equations simultaneously

I need to find the value of Ta and Tc for two simultaneous equations to get a numerical answer using NSolve. I have tried using FindMinimum and NMinimize and still could not solve the problem. Here is ...
4
votes
5answers
148 views

Generate random non-zero “island” in matrix of zeros

I'm trying to write a code which will generate a 3 dimensional array of 0s, then pick some random location in the array, and subsequently expand contiguously to random neighboring sites until a set of ...
2
votes
2answers
90 views

Table with varying step

I would like to produce a table Table1=Table[{j,j^2},{j,0.0001,Pi,Deltaj}] where Deltaj is 0.0001 for j < 5*10^-3 and 0.01 ...
1
vote
0answers
45 views

How to create model for classification using SVM methods?

I have a matrix for diseases associated to their symptoms, the columns represent symptoms each row is a disease. the labels 1 and 0 in the matrix data sets represent when a disease i related to ...

15 30 50 per page