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Questions seeking help understanding error messages and fixing errors.

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0answers
19 views

Understanding BoundaryMeshRegion error

I am trying to calculate the difference between two Cuboids: ...
0
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0answers
21 views

DensityPlot for energy dependence of angle

I need to recive densityplot graph for energy dependence of angle, but I have some trouble with it. That's my code: ...
0
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0answers
34 views

How do I export graphics to file on a Linux system? [on hold]

I need export graphics to a .bmp file from Mathematica running on Linux. When a write: ...
0
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0answers
24 views

Document Center Search is not working in Mathematica 11.3?

If I type "Table" (without the quotes, of course) or any other search term into the Documentation Center search, I get: ...
0
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0answers
31 views

Weird fluctuations in DensityPlot

I have a really long multi parameter Lorentzian function: ...
0
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0answers
49 views

Simulating the motion of the Earth around the sun based on Kepler’s laws

I am using Mathematica 10.3. I want fo perform a computational analysis of the motion of the Earth around the sun based on Kepler’s laws. Here is my code so far. ...
0
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0answers
31 views

NDsolve giving error message Infinity::indet [closed]

I have a partial differential equation that contains Tan[theta] and my attempts at solving it with NDsolve, produce the message ...
0
votes
1answer
31 views

Solve command code problem with system of equations

This is my original equation f[x_, y_] = (4 x^2 + y^2)*Exp[-x^2 - y^2]; So I'm trying to find the partial derivatives w/ respect to $x$ and $y$ and set them ...
2
votes
2answers
49 views

NDSolve producing message Power::infy

I am trying to solve geodesic equations in some 3D black hole spacetime. It is a coupled ODE system with boundary conditions. Due to the symmetry of the spacetime, I expect the solutions to be even ...
1
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1answer
37 views
0
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0answers
34 views

Odd glitch in `PrimePi` [duplicate]

When I plot PrimePi, I get an odd graphical glitch for some values of x. For example, this plots fine: ...
1
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2answers
62 views

Ignoring overflows in SDE simulations

I'm trying to compute the average of the solution to an SDE by simulating some of its sample paths and then taking their Mean. The problem is my SDE is explosive ...
2
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0answers
24 views

How can I deal with a SystemException?

I have a list of functions that are being evaluated, using ParallelTable[], and continue to get the error message: ...
3
votes
1answer
93 views

Force a function to report argument type mismatches

As a relative newcomer to Mathematica, I am still frequently caught out by coding errors that, at least by default, MMA does not indicate to the front end, in particular when I define a function and ...
0
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0answers
16 views
2
votes
1answer
39 views

Understanding this Set error

Given the toy vector: ...
0
votes
1answer
40 views

Where can I download the ErrorBar Plotting Package? [closed]

I'm trying to find the link to download the ErrorBar Plotting Package but I just can't seem to find it. The only link I have is the following: https://reference.wolfram.com/language/ErrorBarPlots/...
8
votes
1answer
86 views

How to use reverse scaling function with error bars?

I have data which I would like to plot along with the corresponding error bars: ...
0
votes
2answers
56 views

Need help with ODE producing error ParametricNDSolve::dsvar: [closed]

The function below is a function of the independent variable a with parameter n0. My goal is to get numerical value for ...
0
votes
1answer
56 views

System of equations produces error message and no solution [closed]

I am trying to solve a set of 9 equations. I keep getting an error letting me know that tag plus in a variable is protected. please help. ...
0
votes
2answers
83 views

Runge Kutta fourth order [closed]

I´m trying to run a fourth order Runge Kutta in Mathematica but the thing is that I´m so so new in Mathematica that I am not even sure what I´m doing. I have these two coupled equations: $$\frac{dy}{...
0
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0answers
33 views

Correcting integration error by supplying assumptions

I wrote some auxiliary functions to help evaluate my main function ELC, which always return the error Unable to prove that integration limits {0, t} are real. ...
2
votes
0answers
27 views

Can custom “operator records” be defined and used in Wolfram System Modeler (and the WL)?

From an answer to a Modelica-related question on SO I learned about the possibility to overload operators in Modelica by using spezialized class operator record. Looking into the Modelica specs for ...
2
votes
1answer
25 views

AssociateTo with a variable as an argument produces error

The following code: list=Table[<\"number"->i|>,{i,1,100}]; list[[20]]["number"] list[[1]] AssociateTo[list[[1]],"number"->101]; list[[1]] Results in....
4
votes
1answer
46 views

Error in Mesh Region during concave hull

I have the following data: Data.csv It crates the following image: Im trying to make a concave hull so that I can create an outline of the region. I have tried to use all versions of the ...
3
votes
2answers
35 views

Nesting ParametricNDSolveValue

I have a problem nesting the function ParametricNDSolveValue. The documentation does not help so I hope to find some answers here. A minimalistic example for my problem is: ...
3
votes
2answers
105 views

Solving an 'odd' differential equation with NDSolve

I need to solve a differential equation of the type $\qquad \partial_{x_1}y(x_1,x_2)= y(x_1,x_1)\,y(x_1,x_2)$ with initial condition $\qquad y(0,x_2)=x_2$. Now if I try to solve this with NDSolve ...
3
votes
1answer
89 views

Why did Set work instead of SetDelayed?

I started with the following expression a[t_] := -Pi Sin(Pi/2*t) where initial velocity is 2 Pi and initial distance is 1. ...
3
votes
2answers
86 views

Implementing Gauss–Laguerre quadrature for double integral of oscillatory function

I need an efficient way to evaluate a certain double integral for a wide range of parameters: $$I=(\gamma_l \gamma_L )^{3/2} \int_0^\infty \int_0^{1} \frac{r ~d r ~dx}{\sqrt{r^2+b^2 x^2}} \times \\...
0
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0answers
41 views

CompiledFunction::cfexe: error without compiled function

I get the error: CompiledFunction::cfexe: Could not complete external evaluation; proceeding with uncompiled evaluation. but I am not using any compiled function in my code: how can it be ...
4
votes
1answer
133 views

Interpolation of data

Consider a set of data points ...
2
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0answers
44 views

Why do I get this warning when replacing pattern with list element? [closed]

The input x^2 + x^3 /. x^i_ -> i yields: 5 The input u = {1, 2, 3} x^2 + x^3 /. x^i_ -> u[[i]] still yields the ...
2
votes
2answers
65 views

“Forcing output of a function to be Real in Mathematica” Non-linear optimization

I am trying to solve a Nonlinear optimization problem with Mathematica. Since the maximization problem includes exponentiation with fractional power, the result generates the complex numbers that stop ...
0
votes
0answers
48 views

Numerical integration gives errors NIntegrate::slwcon: and Integrate::eincr:

I have a problem with numerical integration of this function: ...
0
votes
1answer
69 views

Non-linear optimization giving error NMaximize::nrnum [closed]

I am trying to solve the following non-linear optimization problem: Here is my code: ...
0
votes
2answers
53 views

Why do I get a Partition::pdep error?

I've been running an iterative job (j=1,2.,3,.....300,000,000). The vast majority of steps proceed smoothly. Every several million or so steps, I get a "General::inf: Input matrix contains an infinite ...
0
votes
0answers
44 views

Second order ODE systems should be equivalent to first order systems but DSolve gives error with second order

I'm trying to solve a physics problem using DSolve, and I've been getting varying degrees of success depending how I write down the equation. Here is what worked: ...
0
votes
1answer
23 views

SubtractFrom::rvalue with Compile

I want to compile the code described here, but I get the error: SubtractFrom::rvalue: 1.`*^8 is not a variable with a value, so its value cannot be changed. A minimal non working example could ...
3
votes
1answer
116 views

Indeterminate result from Sinc

I have an impulse train given by (1 + Csc[(π x)/(1 + R)] Sin[(π (1 + 2 R) x)/(1 + R)])/(2 + 2 R) Because of the Csc, ...
0
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0answers
48 views

FindMinimum giving error FindMinimum::infeas:

I'm trying to find the minimum y-coordinate of a point which lies on a side of an equilateral triangle. FindMinimum doesn't work when I change the position of the ...
3
votes
2answers
156 views

Nonlinear system of ODEs with boundary conditions

I'm trying solve this problem: g'(r) = a(r)g(r)/r, (1/r)a'(r) = g(r)^2-1 which have the following boundary conditions: a(0)=n ...
2
votes
1answer
85 views

How to add error bars to a stacked bar chart?

Sorry, I know how to make error bars on normal bar charts, but how can I add vertical error bars to the top of my stacked bar charts, please? ...
0
votes
1answer
59 views

Taylor Series of numerical solution of FindRoot

I have found the inverse to the following equation by using FindRoot. I want to have a Taylor approximation (say starting from ...
0
votes
0answers
55 views

FullForm[1. - (0.3 + 0.4)] gives 0.30000000000000004` [duplicate]

I had a serious error propagation in my computations (Mathematica 10.4.1 Windows 64 bit). After some investigation, I realized the problem comes from something like this: FullForm[1. - (0.3 + 0.4)] ...
1
vote
0answers
54 views

Bizarre error messages when monitoring random integers

I am doing tbl = {}; Monitor[ Do[AppendTo[tbl, RandomInteger[{1, 100000}, 2]], 100000], Length[tbl] ] (well in fact I am doing something less boring but what I ...
-1
votes
1answer
90 views

What is wrong with my fit?

I am trying to fit the following data: data = Import["https://pastebin.com/raw/gHdYLCbA", "Table"] I use the following code: ...
4
votes
0answers
85 views

Value for output of layer is inconsistent (implementing SqueezeUNET from Keras)

I'm attempting to implement this neural network in WL: https://github.com/lhelontra/squeeze-unet/blob/master/squeezeunet.py which is a variant of the SqueezeNet network that does image segmentation. ...
0
votes
0answers
28 views

Hyperbola ContourPlot missing input

I'm trying to plot a hyperbola using ContourPlot, but I can't understand what I'm missing on its call. The error says it's incorrect syntax, although I can't see any errors. ...
1
vote
1answer
60 views

NDsolve and Coupled first order ODE solving [closed]

I am new to this community and also to Mathematica. I am trying to solve a set of coupled first order differential equations related to the shape of a liquid drop. The code is as follows : ...