Questions tagged [broken-code]
Use this tag only if you did your research and you still don't know why your syntactically correct code does not work.
65
questions
0
votes
1answer
29 views
ParametricPlot on Piecewise function not working with consecutive t values [closed]
I am trying to graph a piecewise function composed of a series of parametric cubic functions. I initially created a ParametricPlot for the first four pieces of the equation and it was working fine, as ...
0
votes
2answers
56 views
Unable to find the exact dimension of an expression
I have defined a variable called y, this contains a huge equation, but when I look for the dimension of y it shows 3. How come a single expression has dimensions of 3? It is supposed to be 1 right?
<...
0
votes
0answers
54 views
Fourier Transform and Inverse Fourier Transform of Lists
I am trying to compute the Fourier transform of a list, say an array of the form {{t1, y[t1]},.....{tn, y[tn]}}; apply some filters in the spectral components, and then back transform in time domain.
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2
votes
1answer
43 views
User Implemented SHA-1 is failing for strings of length >512 bits
So, earlier, I posed a question regarding getting a user implemented SHA-1 hash function to work correctly. Well, I fixed the problems, cleaned it up a little bit, but now I have the problem for when ...
1
vote
1answer
104 views
Q: How to manage notebook crashes, “In a previous session”, and memory consumption?
I worked in a notebook. Something went wrong. I do not know what or why. The notebook did not react anymore and closed.
After it, I try to open the same notebook. Then the next text appears:
"The ...
0
votes
1answer
254 views
I can't solve system of differential equations with Dsolve
Here is the code and the system, and it is supposedly analytically solvable.
$$\frac{dx(t)}{dt} = i(\frac{3w}{2}x + ke^{2iwt}y)$$
$$\frac{dy(t)}{dt} = i(kxe^{-2iwt} +\frac{3w}{2}y)$$
and my code ...
0
votes
1answer
118 views
Help with debugging my code [closed]
In order to descrive the multifractal behaviour of a set, Baumann provides a code based on the functions Dq and Tau, given below.
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-2
votes
1answer
108 views
1
vote
2answers
124 views
I have two lists that are the same, yet I get a FALSE when i try to show they are equivalent
I have tried changing the variables, reevaluating the cells, but it just keeps giving me false. The weird part is that it was originally true and it changed to false, randomly.I did not want to post ...
0
votes
1answer
72 views
Do-loop with ParametricNDSolveValue not giving expected results
I have written code that using a Do-loop. In the loop I am changing the value of x, v, l and R, and looking at the computed ...
0
votes
1answer
34 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 ...
6
votes
1answer
318 views
What is wrong with this code? (Usage of FunctionInterpolation and how to make code efficient)
I am trying to create an interpolation out of a function that comes from an improper integral. The end goal is to make a 3d plot over a specific region. Specifically, I have the following code:
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1
vote
0answers
128 views
1
vote
2answers
61 views
MaxValue does not use composed function correctly
I used the compose operator on two functions (a vector-valued interpolated from ndsolve composed with Norm) and then passed the result to MaxValue, which works fine only if I reapply the norm. What is ...
2
votes
1answer
77 views
Code for finding multiple roots only finding two
I've an issue with my code. I am basically trying to get the n-th root of a function. My code finds two roots correctly, but for others, which I think should be distinct, I get the two roots repeated ...
1
vote
0answers
79 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:
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3
votes
2answers
156 views
Extract mesh coordinates from a LaplaceSolution Plot
I have made a code for the solution to a particular problem involving the Laplacian, and after plotting in 3D the resultant potential, I have tried to look for a ...
2
votes
0answers
40 views
How can I fix this cycle in order to iterate several times? [closed]
I have been working on a code whose only purpose is to get the mean value over four numbers. And I managed to do one cycle, however after trying to repeat this process until a certain condition is ...
2
votes
1answer
109 views
How to combine Graphics primitives in a DynamicModule without breaking it
I am trying to present Graphics primitives dynamically. I want the displayed image to be able to update after the user changes the controls. An example would be ...
0
votes
2answers
378 views
Michaelis–Menten kinetics using Gillespie Algorithm
I am trying to implement Michaelis–Menten kinetics using Gillespie Algorithm.
$$\text{Reaction 1:}\quad E+S\rightarrow C$$
$$\text{Reaction 2:}\quad C\rightarrow E+S$$
$$\text{Reaction 1:}\quad C\...
6
votes
2answers
126 views
NonlinearModelFit inside Manipulate
I can't understand why this behavior with my code... I'm trying to visually adjust the best parameters to fit my model, everything is working fine, less the part of adjusting the model.
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0
votes
1answer
97 views
Why this expression doesn't work?
I am trying to choose a function and then the parameters using Manipulate, but isn't working...
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5
votes
2answers
150 views
A box structure with a depth exceeding the maximum allowed depth was encountered
I am trying to perform the task in Mark McClure's article Parametric L-Systems and borderline fractals. I have copied his opening code on the first three pages:
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-3
votes
1answer
95 views
Help with NDSolve for system of odes [closed]
Can someone please tell me what I am doing wrong? I am trying to solve a system of odes using NDSolve. The code I have written is as follows:
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1
vote
1answer
89 views
Please help me find my error [closed]
When I use variables, errors are encountered. But when I change the variables to constants, I don't have a problem, but I wonder why.
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0
votes
0answers
32 views
How to get a full name function [duplicate]
I have some function in string format,and I can get it short name without context
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3
votes
1answer
330 views
Label State Space Models converting ODEs
Say I have a set of differential equations not necessarily in first order form. I would like to build the corresponding state space model. When equations are many and long, it becomes difficult to ...
3
votes
1answer
104 views
1
vote
1answer
61 views
Defining constants inside a script?
At the beginning of my script, I define a constant E by writing E:=2u+2uv, but then at the end of the script after running the final command, the result comes out with the form K/(2u+2uv). My question ...
-5
votes
1answer
168 views
How to get the coefficients of a generator function? [closed]
I am trying to programming the following in Mathematica; however I am having trouble getting this to work inside the For loop.
$$\text{For}\left[i=1;i^2<10,i\...
0
votes
1answer
79 views
I just don't see the difference
I checked it by hand and i am sure that the first code does what i want it to do. But i just don't get even by calculating by hand why the 2nd code is wrong.
The only difference in the two codes is ...
3
votes
2answers
572 views
Solving a reaction diffusion dystem [closed]
I have a problem solving a numerical reaction diffusion equation. It emits the following message:
RecursionLimit::reclim2: "Recursion depth of 1024 exceeded during evaluation
How can I solve this ...
6
votes
2answers
401 views
Sound synthesizer using Manipulate
Sound synthesizers, both digital and analog, often include a parameter section for shaping the amplitude of a sound wave over time. This parameter section is commonly known as an "ADSR EG" (attack, ...
1
vote
0answers
144 views
How to suppress the Windows crash report dialog results from Mathematica sporadical crash when the code is running [closed]
This problem occurs in mathematica 10.0 for windows 7 64 bit.
The dialog box in the center of the picture shows that "mathematica kernel for windows has stopped working". I don't know when this error ...
-5
votes
1answer
95 views
Can't get plot using the Evaluate function [closed]
I am trying to plot a series of five curves using a loglogplot command and then labeling the curves with a value. This is the program I am trying to run.
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1
vote
1answer
231 views
ParametricPlot3D shows an empty box
I'm trying to visualize numerical solution of 4 differential equations (these are the coordinates of a wave function in a quantum mechanical system):
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1
vote
0answers
30 views
Inconsistency when adding a variable to an analysis
I have a system of three ODEs that I want to find the steady states of, and whether or not they're stable via a simple analysis. To do so, I just calculate the eigenvalues of the Jacobian evaluated at ...
10
votes
2answers
501 views
What is the Difference Between Rule (->) and RuleDelayed (:>)?
I am new to Mathematica so this question may seem rudimentary. Sorry for that! :)
I want to implement the well-known property of Kronecker's Delta
$$\Sigma_{i=1}^{n} a_i \delta_{ij}=a_j,\quad 1 \le ...
1
vote
1answer
545 views
NDSolve: Indeterminate expression 0. ComplexInfinity encountered? [closed]
The following code give errors that I don't understand.
Could you please suggest a method to solve these differential equations?
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0
votes
1answer
55 views
Second order differential equation, with term from previous numerical solution
I have a second order differential equation, in terms of a term that was previously obtained from numerically solving another equation.
Numerical solution of equation before 2nd order equation:
<...
1
vote
3answers
253 views
Solving cubic equation with unknown coefficients
I am trying to solve a cubic equation with unknown coefficients (p and t), here is the code:
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-7
votes
1answer
114 views
My program to model exterior ballistics doesn't doesn't produce the plot I expect
Here is my program to model exterior ballistics. It doesn't doesn't produce the plot I expect. How can I fix it?
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0
votes
1answer
107 views
Lagrange multipliers implementation (beginner question) [closed]
I am trying to write a code to find the minimum of $f(x,y) = (Mx + Ny) \,/\sqrt{M^2 x + N^2 y}$?, subject to the constraint $g(x,y)=x+y-1$. Also, $x,y>0$, and $M$ and $N$ are positive constants.
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0
votes
1answer
48 views
Variable Definitions and Random Numbers [closed]
I have currently created the following matrix:
m={{RandomReal[{0,1}],RandomReal[{0,1}]},{RandomReal[{0,1}],RandomReal[{0,1}]}}
In other words, a $2 \times 2$ ...
2
votes
1answer
160 views
Why different output is obtained for the same code (Mathematica 10.1)?
I wrote some code in Mathematica:
...
9
votes
2answers
4k views
How to set up a simple Monte Carlo simulation?
there is a 1% chance that there will be a scattering event, if there is a scattering event the direction of scattering will be determined by a random sample of the custom[a_] function and if there is ...
2
votes
1answer
304 views
Getting errors when I try to evaluate code taken from Trott's Mathematica Guidebook for Graphics
I would like to learn how to make high quality images in Mathematica. In my pursuit, I have come across Michael Trott's Mathematica Guidebook for Graphics. I have been trying some of the examples, ...
0
votes
2answers
167 views
Replace $z$ with interpolated function and plotting
I start off with this equation $z(x,y) = sin(xy)$. I create an interpolation from $0 < x < 5$ and $0 < y < 5$.
I then use this interpolation on a simple function $w(x,y) = x + y + z(x,y)$
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4
votes
1answer
634 views
Issue in ParallelTable after evaluating another function using NDSolve and FindRoot. What is wrong with this inverse?
I am trying to find the inverse of a function which is defined through NDSolve and NIntegrate.
The question is pretty similar ...
1
vote
1answer
270 views
Error message: Coordinate index 0 is out of range for the enclosing GraphicsComplex
I am unable understand following error message: Coordinate index 0 is out of range for the enclosing GraphicsComplex. How to fix it?
Attached data here: pts and polygons. See also end of question.
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