0
votes
1answer
10 views

Getting RandomChoice to work in Manipulate function

I'm a beginner mathematica programmer and I am tryin to create my first demonstration. This code should represent what happens if one changes the size of the reading frame, calculating the nucleotide ...
2
votes
1answer
23 views

HoldForm does not Hold Form for fractions sometimes

I'm facing a strange behavior of HoldForm. I need to display 1/2*3/4 in LaTeX like this : $$ \frac{1}{2} \times \frac{3}{4} $$ ...
0
votes
1answer
32 views

Obtaining the relations of variables using diagonal matrices

I know this is too an elementary question, but I am a pathetic newbie in mathematica and I cannot find any answer by googling. What I want is obtaining some relations of unknown variables using their ...
1
vote
2answers
89 views

Generate nonoverlapping random circles

I want to distribute n circles unformly in an area(e.g. free plannar space). The circles could touch each other but cannot overlap. ...
0
votes
1answer
30 views

WorkingPrecision causes issue in the NIntegrate

I really can't figure out why my code sometimes is not working. My integrations involve two variables (k and kz). The integration range for both of them are from zero to infinity. I found out that in ...
4
votes
0answers
35 views

Alternatives to FiniteElement as Spatial Discretization Method for NDSolve

Finite Element Programming: [...] It is possible to skip this section and continue with the discretization stage and make use of the initialized data structures ...
1
vote
0answers
20 views

Error message with RegionPlot after SetOptions

I get an error message with SetOptions[RegionPlot, ImageSize -> Medium]; RegionPlot[u v (1 - v) >= 10, {v, 0, 1}, {u, 0, 100}] that says ...
1
vote
1answer
79 views

Partial differentiation mixes up variables

Consider $$ U \equiv \dot{\theta} - \theta \ ,$$ where as per usual $\dot{\theta} = \frac {d \theta}{dt}$. We then have $$ \frac {\partial U}{\partial \theta} = -1 \quad , \quad \frac {\partial ...
2
votes
1answer
31 views

Double application of NIntegrate produces unexpected error messages [duplicate]

In the course of trying to answer 69601, I encountered unexpected error messages. In highly simplified form, NIntegrate[NIntegrate[z y, {y, 0, 10}], {z, 0, 10}] ...
0
votes
1answer
33 views

NonlinearModelFit - “Encountered a gradient that is effectively zero”, all variables are 1, 1, 1 [duplicate]

I have data of the form {149.45, 0.371093}, {149.362, 0.375976}, {149.277, 0.380858}, ... }, where each element of the list is {x, y}. The plot of this, using ListPlot, gives an approximate Gaussian. ...
0
votes
0answers
25 views

Fundamental group Pi1(SU(n)) and Pi2(SU(n)) [migrated]

I need to find a fundamental group Pi1(SU(n)) and Pi2(SU(n)) for any n. Can you help me? I don't have any idea. SU(n) is the group of all unitary matrices with determinant 1 and "Pi" has the intended ...
0
votes
0answers
35 views

Fourier Transformation of a List

As we know the FourierTransform goes a function of t ,for example, f[t] to ...
0
votes
1answer
47 views

Display 3D function and its gradient in same graphic [duplicate]

Is it possible to display e.g., $z=x^2+y^2$ with Plot3D and in the same box, in the $z=0$ plane, plot its gradient?
7
votes
3answers
208 views

How would I return a random Mathematica command?

I'm doing some metaprogramming. How would I make a Mathematica function that returns a random Mathematica command? Is there a list of command names that I could use ...
-4
votes
0answers
35 views

how to revese-derive a function [on hold]

I would like to get the L function in this derivative: $$ \tau = \frac{d\mathbf L}{dt} $$ I have the value of τ. I am not familiar of derivations and I do not know if t is a variable, if it does ...
0
votes
1answer
46 views

Solve with limit over multiple variables

Very new to Mathematica so apologies for what is probably numpty question. The following returns no solutions. However, there is a solution! If I set a = 1 I get the solution b = 1/2. Can you explain ...
1
vote
1answer
41 views

Why does NMaximize does not follow the constraints that were given to it?

(someone may want to mark it as a duplicate, but I still have to ask! I just can't figure out why!) ...
1
vote
0answers
41 views

ImageResolution Doesn't Work!

The code below is supposed to generate a high resolution plot, but it does not! g = Plot[Sin[x], {x, -1, 1}]; Export["c:/sin.jpg", g, ImageResolution -> 600] ...
1
vote
1answer
118 views

Sinusoidal Wave over a Circle

A sinusoidal wave can be plotted in a two dimensions. Generally and simply : y[x]=Sin[(2pi/lambda)x] As it is being plotted, the horizontal axis (as a straight ...
8
votes
3answers
148 views

Truncating a list once all members of a set have appeared?

Consider if you would the case where we have some list of elements: list0 = {54, 4, 7, 9, 3, 54, 4, 20, 2, 456, 2, 3}; And we have some target list: ...
1
vote
1answer
32 views

Sum of two Piecewise functions give wrong vector

I would like to calculate the normal at a certain point of a parabola. The parabola is defined only on a certain area according to a Piecewise function. Afterwards ...
2
votes
1answer
29 views

Substitution breaking the scope

A novice's problem, perhaps: it seems that /. substitution does weird things to the scope. ...
0
votes
2answers
26 views

How to share numbered variables between kernels

Supose I have two variables v[1] and v[2]. I used: SetSharedVariable[{v[1], v[2]}] Then, ...
1
vote
0answers
51 views

“Home Edition” license for Mathematica: country and upgrades [on hold]

I'm interested in buying a "Home Edition" license for Mathematica, but there's the following information which I'd like to know beforehand and which I cannot find online: As I'm about to buy it, the ...
1
vote
1answer
67 views

Substitution in parameters to “Which”

Why in this expression ...
1
vote
0answers
28 views

Which operations preserve digit precision?

Imagine I had to use numbers with a 600 precision digits. Do all mathematical operations, like +,-,...
1
vote
1answer
58 views

Two dimensional high oscillated numerical integral

I have some problem with two dimensional integral. I want to calculate such integral. ...
2
votes
0answers
56 views

How to combine several plots with this special alignment? [duplicate]

How can combine different plots just as shown in the image? Just give codes about one example plot,and tell me how to create plots as the form as gaven. Follows are codes: n = 2; z = 200; [Alpha] = ...
-1
votes
0answers
42 views

How does NSolve return? [on hold]

I have purposely made 2 functions which do not have real roots. For the first function, NSolve gives me back an empty list which is correct. But I don't get why for the second function, NSolve gives ...
4
votes
0answers
40 views

HEALPix grid on a sphere

Are there any Mathematica tools for using the HEALPix ( Hierarchical Equal Area isoLatitude Pixelation) grid on a sphere? It is commonly used in astronomy, but I have not found any Mathematica ...
3
votes
1answer
109 views

Ruth-Aaron quadruple challenge

This a computational challenge, to find an efficient algorithm to discover a quadruple $(n,n+1,n+2,n+3)$ with the same sum of prime factors as described in the MO question, "Ruth-Aaron triples, etc." ...
1
vote
0answers
47 views

The problem (time) caused by ?NumericQ

In here, I asked a related (similar) question. Using ?NumericQ seems have slowed down the entire calculation. But I now have a more serious problem: ...
1
vote
2answers
55 views

Expressions containing globally undefined symbols inside a function where they are defined

Consider the following code. f[a_,b_]:=x; Clear[a,b]; x=a+b; f[1,2] It returns a+b. However, from a certain viewpoint, one ...
1
vote
1answer
28 views

Nested list element at position specified by a list

I'm trying to avoid constructions like Y[[X[[1]], X[[2]], X[[3]]]]. That is we have a nested list (Y) of depth $n$ and another ...
0
votes
0answers
35 views

Exctrating data information from a file.txt

I really did previous long search in the site and I couldn't find any answer that might help me. So I am asking it. I have the following data set, ...
2
votes
2answers
73 views

How discretize a region placing vertices on a specific non-uniform grid

Given a generic region, for example: \[CapitalOmega] = ImplicitRegion[ 2 x^2 + 3 y^2 + 2 x y - 2 <= 0 \[And] x^2 + y^2 > .1, {x, y}]; and a ...
-7
votes
0answers
42 views

Data-Analysis and optimization [duplicate]

I have the following set of data, I want to write a program that will reduce the list on each set by, division of 100 and keep the maximum, don't divide the maximum. a = {{{2, 3, 1, -3, -5, 2, 6, -1, ...
0
votes
0answers
38 views

ConversionRules and style inheritance

Take the LaTeX-Article stylesheet stylesheet = FileNameJoin[{"Article","LaTeX-Article.nb"}]; Compare these outputs ...
3
votes
2answers
119 views

RegionPlot from NDSolve

I am having quite a headache using RegionPlot to see the region of acceptance of certain coupled differential equation. I shall elaborate and try to be as ...
0
votes
0answers
60 views

Exporting graphic to pdf acting funny

I have a plot created in a notebook that I usually would right click on and choose Save as pdf. It worked fine until this morning. Shown below, the first plot is what I used to get. The second plot is ...
3
votes
2answers
143 views

How to cut a thick curve in half lengthwise?

Is there any easy way to cut a thick curve in half lengthwise? Example: suppose I have the cardioid shown in the figure below, is there a way to delete either the inner or the outer portion of the ...
3
votes
2answers
103 views

Solving a discontinuous differential-algebraic equation system for plasticity behaviour

I need to solve a discontinuous equation which is typical in theory of plasticity. For a simple case I get the following equation system (reformulated for numerical implementation): $s(t) = ...
0
votes
0answers
45 views

Printing mathematica file [on hold]

I did some plots on mathematica and then I saved them as a pdf file. I'm facing a problem when I print these files some of the grid lines on the plot disappear in a random way even though they appear ...
1
vote
1answer
81 views

Can't install Workbench on Surface Pro 3

I've been trying to install Wolfram Workbench 2 for a few days on a Surface Pro 3 i5 256 Mb, Windows 8.1, Mathematica 10.0.1, Java 8, without success, I'm getting a bit desperate. For the Eclipse ...
0
votes
0answers
58 views

How to randomly create disks with randomized radii under given specific cover ratio?

I want to create uniformly distributed disks(dots) in a specific rectangular area. Suppose: the disk radii should be uniformly between $a$ and $b$ ($0<a<b$); there is no interaction between ...
0
votes
1answer
52 views

Plot a table of functions with different color [duplicate]

I have a function with two independent variables: SNR[t_, f_] := 20 Log10[1/(2 Pi f t)] And I have a list for "t" ...
1
vote
1answer
92 views

Complex Integration

There are some sequential functions: ...
0
votes
0answers
32 views

How to show “AxesLabel” when “Frame -> True” [duplicate]

I'm using Mathematica 9.0.1, and using "LogLinearPlot" function. My problem is when I enable the "Frame", and set "AxesLabel", the labels won't be shown. If I disable the "Frame", the labels are ...
1
vote
0answers
86 views

How to make a graph of this function?

I need to plot the following function: ...
2
votes
1answer
75 views

Intelligent vertex placement in large tree graphs

This question about graph layout is fairly general, but can be illustrated in the case of the Collatz Conjecture. Collatz created the following function over integers greater than 1: If the integer ...

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