Questions tagged [error]

Questions seeking help understanding error messages and fixing errors.

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27 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
126 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, ...
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1answer
70 views
0
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0answers
74 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
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2answers
248 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
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1answer
289 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
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1answer
83 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 ...
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0answers
76 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
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0answers
95 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
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1answer
124 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
1answer
123 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. ...
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0answers
86 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
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1answer
75 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 : ...
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2answers
56 views

How precisely does Mathematica handle/record an isolated error in one of a long series of separate calculations?

I'm generating a series of (numerical) matrices, and testing each one for a certain property, and trying to estimate what proportion possesses that property. I write out the result at every million-th ...
1
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1answer
25 views

How to display the error in interation in a comfortable way?

For example t = 0.5; Do[t = Module[{a = t}, c = (a^2 - 2)/3;Pause[1]; err = c - a; c]; Print[err], {i, 100}] I want to see the ...
1
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1answer
89 views

Why is this function indeterminate?

Consider an impulse train 1/(R + 1) + (Sum[Cos[(2 k π x)/(R + 1)], {k, R}])/(R + 1) For x=0 it's clear that this function ...
0
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2answers
136 views

How can I avoid the message Infinity::indet?

I have an impulse train of frequency R: 1/(R + 1) + (Sum[Cos[(2 k π x)/(R + 1)], {k, R}])/(R + 1) For ...
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1answer
40 views

Cannot set DownValues to ValueList while loading package

I have installed a package named HEP from Wolfram Library Archive which contains several .m files by Files -> Install (...
-1
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1answer
40 views

Unexpected SetDelayed error while using a function with RGBColor [closed]

...
0
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2answers
178 views

Why does my Solve output contain this symbol? [duplicate]

I have a pair of coupled polynomial equations that I need to solve, so I tried using Mathematica's solve tool. This is the code that I wrote: ...
2
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1answer
140 views
1
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0answers
126 views

NDSolve problem: Power::infy: Infinite expression 1/0. encountered

I am trying to solve system of 15 differential equations: ...
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0answers
60 views

Getting max precision limit overflow for a very simple calculation

I've never seen this error on such a simple calculation. Does anybody know how to fix this annoying error?
0
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1answer
102 views

Errors using FindRoot on slow numerical function

I would like to find the solution of an equation containing a slow function FindRoot[func[x, onsideS, hoppingS, 0.01] - (1/E) == 0, {x, 1,10}] for different ...
0
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1answer
105 views

NIntegrate::zeroregion error

While integrating the following function, ...
0
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2answers
41 views

Force a result from “Indeterminate” for single impulse?

The formula for a single impulse of amplitude $1$ at $x=r$ is given by $$\frac {\sin (\pi (x-r))}{\pi (x-r)}$$ (In MathJax because it's a math formula.) Formally, at $x=r$, this function evaluates ...
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0answers
26 views

Why do some manipulate/animate become error plots after notebook closed [duplicate]

I have some Manipulate/Animate plots (mostly relating to geometry and geography) which look good after evaluation. But when I ...
2
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1answer
142 views

How do I use FindMinimum with the LevenbergMarquardt method?

Below is my program. I don't know how to define the function f to make it work. Another question: When I define f as a vector ...
2
votes
1answer
75 views

How to reuse variable - Error: Pattern appears on the right-hand side of rule [closed]

I do not know enough about Mathematica to understand why the following statement won't save the variable for me for later use: x_fake = Table[i, {i, 1, 100}] It ...
2
votes
1answer
62 views

Getting error message from NSolve

I'm trying to solve for coefficients $k1$, $k2$, $k3$, $k4$ in the following equation: $\det\left(\,\begin{bmatrix}k1+k2 & -k2 & 0\\-k2 & k2+k3 & -k3 \\ 0 & -k3 & k3+k4\end{...
0
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1answer
144 views
6
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1answer
112 views

Passing options to GraphicsRow

I'm trying to pass the options to a simple function based on GraphicsRow as in the example below, but I get a long list of errors. ...
2
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2answers
161 views

Attacking a “Mathematica can't solve” problem

Mathematica throws the following message when I try to solve the equation below "Solve::nsmet: This system cannot be solved with the methods available to Solve". Setting $P_T = 0.5$, $\sigma=0.1$ ...
2
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1answer
122 views

Kernel forever running with no error message. Solve NDSolve without FEM?

I am trying to solve the following reaction-diffusion equation where R_L represents the reaction rate of L. ...
4
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2answers
159 views

Replace solution of NDSolve into another NDSolve

I was wondering if it was possible to replace the solution of L'[x] (which is dependent on r[x], ...
2
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1answer
222 views

Receptor/Ligand Diffusion Michaelis Menten Equation

I'm trying to model the diffusion of a ligand that is binding to a receptor (similar to the enzyme substrate model) where the reaction is I tried using this question as a reference. I'm mainly ...
0
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1answer
52 views

Recursion depth problem inside a loop

I am solving a system of equation inside a loop. This is my code: ...
2
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3answers
136 views

Using DSolve and NDSolve for 1D steady-state diffusion equation with a reaction term

I am trying to solve for a 1D steady-state diffusion equation (Fick's Second Law/Heat Equation) with a reaction term. I wanted to compare using both DSolve and <...
1
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3answers
100 views

ParametricNDSolveValue::nlnum error in conjuction with NonlinearModelFit

I am trying to use ParametricNDSolveValue with NonlinearModelFit in order to fit a differential model to some data. I am following the documentation here under Applications/Parameter Fitting: http://...
3
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1answer
108 views

How to force assumptions for solving a system of equations?

I am trying to solve a system of equations for the panel method using complex functions. Mathematica would not even attempt to produce a solution for the bcs term ...
0
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0answers
60 views

Error with NIntegrate

I am using NIntegrate and getting an error message ...
1
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0answers
62 views

What am I doing wrong in calculating the mean square error? [closed]

I am trying to compare the results of estimators from least squares and quantile regression from the perspective of the mean square error (MSE). The steps for performing this Monte Carlo approach are: ...
4
votes
1answer
144 views

What could be the reason for for the residual error in post-iteration to high…?

Recently I started having this error in my simulations in AceFEM. For me it is quite strange because it happens in a particular step when the convergence has ...
1
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0answers
91 views

NDSolve with Piecewise : an initial value problem? [closed]

I'm working on differential equations and I first used a potential without Piecewise. But given that I wanted to constrain the values between 0 and 1, I started to use Piecewise in the potential, ...
0
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1answer
40 views

Function with numerical integrals, Plot3D works but NMaximize doesn't [duplicate]

I have the following problem: I have a function enter code hereH depending on two numerical integrals g and ...
1
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0answers
62 views

Filtering list using function values [closed]

I have a list (Basis) of size $2^{21}$, and a binary function $A$ defined on it (only outputs 0 or 1). I want to filter out the items from Basis that $A$ sends to 1. I was able to find the size of the ...
1
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0answers
60 views

Having trouble finding the path of a projectile with NDSolve [closed]

I have a system of differential equations that models throwing a projectile with air resistance. I want to find the value of $a$ that will maximize the distance of the throw. I don't know why, but I ...
1
vote
1answer
183 views

Mathematica 11.3 ListLogPlot gives strange error [closed]

Trying to make a very simple Log plot with Mathematica 11.3 on Ubuntu 17.10 ...
4
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1answer
289 views

Wrong complex integral

I've tried to perform the following integral with mathematica (student edition): ...
0
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1answer
79 views

my ODE won't get solved [closed]

I press ENTER but nothing happens. Not even the {}. Nothing. DSolve[{y'[x] == (-x*y[x] - 1)/(4*x^3*y[x] - 2*x^2) }, y[x], x] Have I written anything wrong?