1
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1answer
129 views

using Module in NDSolve

I am trying to solve a set of two wave equations where solution of first equation defines initial conditions for the second one. And I would like to use Module to define those equations as a function ...
1
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1answer
116 views

NDSolve inside Module with local variables

I want to use NDSolve within a Module and output the solution at some times. (Mathematica 10) All works fine with global variables (symbols) ...
1
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1answer
85 views

Series expansion of InterpolatingFunction obtained from NDSolve

I am trying to obtain a series expansion of the numerical solution of a differential equation. I encounter difficulties going beyond first-order expansions which I believe might be due to my inability ...
1
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1answer
167 views

Solving systems of equations

So I have a set of equations like 12 of them but 13 variables. However I would like to find the numerical value of the roots for the maximum value of a particular variable. I don't know how to do that ...
1
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1answer
90 views

How to checkpoint computations?

Suppose I do some big experiment, presumably in a Table[], or a ParallelTable[]. Experience shows that there is a non-zero ...
1
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1answer
79 views

FindProcessParameters for Fractional Brownian Motion Returns Error

I have the following data: ...
1
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1answer
115 views

Passing function as argument

I've been mucking around with passing functions as arguments to other functions and via trial and error seem to have something that works. I was wondering if someone could have a quick look at some ...
1
vote
1answer
141 views

Under what conditions does Mathematica give a natural antiderivative when integrating?

Natural antiderivative is defined as follows, using Fourier transform: $$f^{(-1)}(x)=\frac{i}{2\pi}\int_{-\infty}^{+\infty} \frac{e^{- i \omega x}}{\omega} \int_{-\infty}^{+\infty}f(t)e^{i\omega t}dt ...
1
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3answers
149 views

How to ReplaceAll independent of depth?

I have a big list which in principle can be described as this more compact list : ...
1
vote
0answers
207 views

Developing easy code to apply Delta Method to generate prediction bands for custom distributions

I think that this is an interesting issue for all those who when to not only adjust one prediction function, but also to obtain the prediction bands to asses the graphical or tabular error I'm trying ...
1
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4answers
130 views

Replacing more than one element from a Sublist

The following expression allows me to extract the value of x and y: ...
1
vote
1answer
131 views
1
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2answers
111 views

How to widen PlotLegends?

I have a plot whose legend, when placed at the bottom, is two lines rather than one: ...
1
vote
1answer
207 views

Front End Find feature broken in Version 10 with OSX Mavericks?

I installed Mathematica 10 and on my Macbook-Pro with OSX Mavricks. I was most frustrated to find that the front-end Find feature doesn't work. Do others have this problem? Is it possible something ...
1
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1answer
178 views

eigenvector bug also for matrix with numeric value [closed]

I just realize that probably there is a bug also in calculating the eigenvector of a matrix with numeric values (see here for bug in eigenvector calculation with symbolic value). In particular in my ...
1
vote
1answer
103 views

How can I define a function that takes a list of reals?

I'm trying to define a function f which takes a list of reals. My purpose is to build a function which I can give a list of reals, integers or strings and have it ...
1
vote
1answer
216 views

Placing many arrowheads on curves

I can't find anything anywhere on the web to help me with this. My plot: ...
1
vote
1answer
166 views

How to check a solution of a partial differential equations?

Here is a system which Maple can solve, but Mathematica cannot. ...
1
vote
2answers
130 views

Few quick Mathematica questions about Dictionary

a. Get the list whose elements are of the form {language,number of words in dictionary) I tried this, and it gave me the number if words in dictionary, but I don't know how to get the language part: ...
1
vote
1answer
204 views

Combining solar system planets orbits and positions in Graphics3D and Show

I am building an animated model of the solar system, where I would like to display the OrbitPaths of the planets along with their ...
1
vote
2answers
223 views

Mathematica can't minimize a function

Mathematica seems not to be able to minimize this univariate function over integer arguments, $r>2, r \in \mathbb{Z}$. ...
1
vote
1answer
268 views

Factor a Vector

Does there exist a function in Mathematica that simply takes out a common factor from a vector/list of expressions? This seems like such a simple operation that I am surprised that I could not find it ...
1
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2answers
216 views

Cropping a Plot without rasterization

Suppose that I make a plot of $x^2$ vs. $x$: myPlot = Plot[x^2, {x, -1, 1}, Frame -> True] If I click on the plot, I see the orange handles with which I can ...
1
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1answer
792 views

Plot Fourier transform of $\sin (2 t)$

I'm trying to plot the Fourier transform of $\sin (2 t)$. I tried using the FourierTransform Function (I'm expecting a peak at w = 2) but it gives me undefined at ...
1
vote
1answer
199 views

Is it possible to give the closed-form of the stiffness matrix of triangular prism element?

Suppose the vertices of triangular prism are 1, 2, 3 (bottom triangle), 4, 5, 6 (top triangle), the coordinates of the vertices are $$ (x_i, y_i, z_i), i=1,2,3,4,5,6. $$ We can write the stiffness ...
1
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1answer
187 views

I want change gamma function form into beta function form

I want to integrate below form ...
1
vote
1answer
465 views

Fourier Series of “Split” Defined Function

Not sure how to phrase this in a concise way, anyway it seems like the function FourierSeries assumes the interval for which to compute the Fourier coefficients of a given function is $[-\pi,\pi]$, ...
1
vote
1answer
231 views

Exporting SmoothHistogram plot data

My program produces a large data set, which is distributed by some unknown function. I've used SmoothHistogram to visualise it crudely as a probability distribution ...
1
vote
1answer
294 views

General form of a linear transformation

Let $v_1 = \begin{bmatrix} 2 \\ -1 \end{bmatrix}$ and $v_2=\begin{bmatrix} 1 \\ -1 \end{bmatrix}$ and let $A= \begin{bmatrix} 3 & 2 \\ -2 & 1 \end{bmatrix}$ be a matrix for $T\colon \Bbb ...
1
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3answers
152 views

automatic processing of numerical results in `Plot`

First I want to solve an equation $F(x,y)=0$ for $y$ by supplying a value of $x$. (suppose obtaining the analytic form of $y(x)$ is too difficult) Then I want to plot root $y$ (numerically calculated) ...
1
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3answers
166 views

Number theory: Problem involving rational numbers

Use RandomRat to test whether ((-1)^(1/Denominator[q]))^Numerator[q] is identical with ...
1
vote
0answers
2k views

How to assign (and retrieve) variables with subscripts? [duplicate]

I like to give subscripts to my variable names when the variables are related. I.e., Subscript[r, i] = 3 3 A problem arises when I later assign ...
1
vote
1answer
568 views

Custom ticks failing with Frame

I know I can manipulate ticks: ...
1
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1answer
350 views

Simplify vector expression - is there something like “Factor” for vectors, dot products etc.?

I am looking for a way to simplify dot products etc. Here is a minimal example: Lets say I have two vectors a and b: Array[a,2] Array[b,2] Now I evaluate their ...
1
vote
1answer
299 views

Print indexed (by subscript) variable name systematically

I have some variables : Subscript[S, 1], Subscript[S, 2]...etc. But they are defined in a for loop like For[g = 1, g < 4, g++, Subscript[S, g] = g]; Later, I ...
1
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1answer
203 views

Need better font control [duplicate]

Generally many programs have a menu item to raise/lower current font size. This is much more convenient than trying to root around in in internal mathematica options. I need to change ALL default ...
1
vote
2answers
403 views

How to implement this simple product rule in mathematica [duplicate]

Firstly i have defined a simple function below. dotPro[a_, b_] := a[1]*b[1] + a[2]*b[2]; Then i create two terms using the above function. ...
1
vote
2answers
336 views

How to plot results of Dsolve

I could not figure out how to get a plot of the results of my coupled differential equations. I am sure that the equations are written correctly. I tried solving a basic Lotka Volterra set of ...
1
vote
1answer
316 views

Selecting morphological components, of a certain size, centered on points of interest in an image

I have a set of points in an image, for example: ...
1
vote
1answer
1k views

Keeping Nonlinear Model Fit Real

So I am using the NonlinearModelFit (NLM) command with a fairly simple function. There are 4 unknowns and the (x, y) points that ...
1
vote
0answers
107 views

Split one string about a fixed width with `SyntaxQ=True`

How to split one string about a fixed width, the string may come from the input or output cell of Notebook. sample string ...
1
vote
3answers
647 views

plot a tube via a 4D plot [duplicate]

I have a function f[x_, y_, z_] := Exp[-x^2]*Exp[-z^2] which traces out a tube along $y$. Is there a way to plot this 4D function, where the plot color is the ...
1
vote
1answer
539 views

Making a ListVectorPlot3D from data in an external file

I have a .dat file with six columns: {x y z vx vy vz}, where x, y, z are space coordinates and vx, vy, vz are the vector components. How can I use this file to get ...
1
vote
1answer
131 views

Format Preservation of FullSimplify on Indexed System of Autonomous Equations

I currently have a large system autonomous differential equations. I've indexed a more managable dummy system of identical form, using Part to reference each ...
1
vote
0answers
112 views

Anti-aliasing won't work when there is PlotStyle command

I've found that if there is PlotStyle command in the input, anti-aliasing will not work. However if the Style code is ...
1
vote
1answer
230 views

Output precision

I've solved some equations using FindRoot and then computed some values. Now when I print the output, I only get a certain precision {{0.01, 496.983, 61.3147, ...
1
vote
2answers
377 views

Import large amount of data with time stamps

I have a large data file (150 000 lines) which I want to import in Mathematica. The first few lines look like this ...
1
vote
2answers
1k views

large matrix eigenvalue problem

I need solve a very large complex matrix (not sparse and not symmetry) eigenvalue problem, e.g., 1e4*1e4 or even 1e6*1e6. How large dimensions of the matrix can Mathematica support? And, how about ...
1
vote
3answers
632 views

Sqrt — how to get negative branch?

One of the many attractions of Mathematica is that integers are generally treated as exact symbolic entities, and not just as numbers. I was just playing with Sqrt, and was puzzled by what appeared to ...
1
vote
1answer
920 views

Plotting a complex function [duplicate]

What does it mean if this message appears: {Im[(1-E^Times[<<3>>] f)/(1-Power[<<2>>] f)]-0,Im[(1-E^Times[<<3>>] f)/(1-Power[<<2>>] f)]-0} must be a list of equalities or ...

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