0
votes
0answers
17 views

How to compute variances from a matrix/table

I have created a matrix/table with an imported dataset. I want to know what the variance is for 3 values at a time but across 68 columns. I would like to do this in an automated way rather than 1 set ...
0
votes
0answers
14 views

Splitting a list into list of lists [on hold]

I am trying to split a flattened list of data into a list containing 4-vectors. Consider the sample set of data (number of elements always a multiple of 4) ...
1
vote
0answers
30 views

Aligning controls and their labels to grid?

I have a Manipulate with 6 sliders controlling 6 different variables. I have labelled them all. The problem is that the labels have different lengths, so it looks a ...
4
votes
0answers
18 views

Explain the difference between ViewPoint and ViewVector?

I've read the documentation, but am still very unclear as to what the difference is between ViewVector and ViewPoint for ...
0
votes
0answers
20 views

Linear interpolation over 2 variables

I'm tuning a function to data over 4-5 variables using Differential Evolution. The objective function calls frequently interpolation function. I came to a point, where compiling the objective function ...
6
votes
1answer
74 views

Undocumented form for `Extract`

Prompted by a comments conversation here, here's an interesting (and often performance enhancing) use of Extract: ...
0
votes
2answers
29 views

Removing a ProgessIndicator when no longer needed

I have a progress indicator in my Mathematica notebook that I update as various calculations are performed: indicator = ProgressIndicator[Dynamic[progress]]; I ...
0
votes
0answers
18 views

A problem with functions and Infinite expression 1/0 encountering

Following code (function) makes integrals and then replace f[x] with Cos functions and calculate the definite parametric ...
0
votes
1answer
26 views

A problem with set values

The following code is just an example to clearly explain my problem. Assume that : ...
2
votes
0answers
34 views

How to get mathematica to simplify a result

I have the following output $\text{Li}_2\left(3-2 \sqrt{2}\right)-4 \text{Li}_2\left(-1+\sqrt{2}\right)$. This turns out to be equivalent to $\displaystyle\log^2(1+\sqrt{2})-\frac{\pi^2}{4}$. How ...
0
votes
0answers
20 views

draw graphics in cycle

Good evening. I've made the following plot g1 := Plot[f[x], {x, -3, 5}] gr1[f_, xmin_, xmax_, slices_] := Module[{span = (xmax - xmin)/slices, ext}, ext[op_, r_] := First@Quiet@op[{f[x], r ...
1
vote
0answers
29 views

Another one problem with legends on GraphicsGrid

I have used ListLinePlot to generate this grid of plots: and I want to add a legend in Row Layout below this grid. My code, has as follows: ...
1
vote
0answers
22 views

An example of how to compute numerically the KL-divergence in mathematica [on hold]

I wanted to compute an exact number for two probabilities that I am comparing. These are two normal distributions as: $$Normal(\mu = 5, \sigma = 4)$$ $$Normal(\mu = 5, \sigma = 5)$$ I decided to ...
1
vote
1answer
92 views

What are these strange shapes in my Plot3D[]?

Plotting a function, I noticed some strange spots away from the main feature, the dark purple here: You can see that they don't actually have any curvature themselves: Strangely, you don't see ...
-1
votes
0answers
34 views

Solving nonlinear system by newton method [on hold]

How to solve nonlinear system by newton method (without Findroot method)? What is algorithm?
1
vote
1answer
68 views

Making mathematica do regulated integrals

Consider the integration, $\int _0 ^\infty dx\ x \tanh( \pi x) \sqrt {x^2 + a^2 } $ where $a$ is a real number. This integral is divergent. We note that an asymptotic expansion of the integrand ...
0
votes
0answers
22 views

Making single letters non-italic in Graphics/Text/Style objects

Suppose that I use Graphics, Text, and Style to type one letter in the subscript of a letter ...
3
votes
1answer
91 views

Scan vs Map vs Apply

I cannot understand the difference between Apply, Scan, and Map. I have tried to play with ...
0
votes
1answer
22 views

How would I enable the Evaluate in place item of the Evaluate menu?

I would like to be able to suppress multiple outputs when a cell is evaluated. Is there a way to enable the "Evaluate in place" menu item of the Evaluate menu?
-1
votes
0answers
35 views

solving simple integral equation [on hold]

Could someone help me finding q(t) so that \begin{equation} \int_x^{x+2\pi/3}q(t)\,\mathrm{d}t = a\cdot\sin{(x)}+b \end{equation} Thanks in advance!
0
votes
0answers
13 views

how to find find a matrix by the characteristic vlaues and vectors [migrated]

Now I am studying linear algebra course, In that for a given matrix we are finding the characteristic values (eigen values) and characteristic vectors (eigen vectors). But my question is why cant we ...
0
votes
1answer
52 views

Create new file, based on 500 articles

I've got a folder with 500 newspaper articles. Each article is saved in a seperate file with a number in the title like "1.txt", "2.txt". Each article has a date but it is not clear in which line the ...
0
votes
0answers
16 views

Is it possible to suppress additive outputs when cells are evaluated?

Is it possible to suppress multiple outputs when a notebook is evaluated? Ideally, I would like to have a notebook with single instances of output. Currently when I open a notebook, I have to ...
6
votes
2answers
141 views

Map structure of irregular list, Flatten then reconstruct list using structure

I'm trying to use Compile[] to improve the performance of an algorithm. The algorithm works on a set of matrices which are not of a similar shape. Unfortunately ...
2
votes
3answers
92 views

Recover data points from RGBColor of known ColorScheme

In general I want to recover the z-values from an image of a DensityPlot. A simple example might just be ...
2
votes
0answers
31 views

$Failed below input area of new cell in notebook

The Mathematica 9 installation on my laptop has developed an odd feature. Just underneath the grey line indicating the input area for a new cell, the expression ...
0
votes
1answer
43 views

Sorting a table of vectors with weights [duplicate]

I'm trying to simplify a table, for instance {{1, {4, 2, 0}}, {4, {2, 4, 0}}, {-2, {3, 3, 0}}, {1, {3, 0, 3}}, {-3, {0, 4, 2}}} Here the first column is the ...
3
votes
2answers
111 views

Mathematica not recognising closed forms as specific values

I have a Mathematica program that outputs a piecewise function, and some parts of the expression are not being recognised as specific numbers when using ...
0
votes
1answer
40 views

Dsolve is not solving equation ( 3 system with 2.order diferantial equations)

I added an image of my equations at the bottom. I dont understand why it is not solving. This is 3 systems with 2.order diferantial equations. I also put my initial conditions. But it is not solving. ...
0
votes
1answer
45 views

Solving System of Nonlinear with Three Differential Equations

I've been trying to solve a system of nonlinear differential equation, but the conditions are a bit weird. Two of the differentials equate to the same equation, but have different boundary ...
1
vote
1answer
84 views

Get Cos[2 x] in “Solve”

My goal is to get an analytical solution of x ( $\lambda$ in the problem), when $\epsilon$ (f[x] in the problem) is maximum (use inverse form). I found that if I can use trigonometric identity ...
0
votes
0answers
38 views

Derive a PDE from other PDEs

I'm trying to do some symbolic calculation like this: Substitute (11.2) into the last two of equations (11.1) and, in turn, substitute these into the first of equations(11.1), I want to ...
4
votes
1answer
81 views

Shift text upwards in graphics so characters with descenders clear horizontal lines

Is there an option to align Text to automatically adjust for font descent? In the attached graphic, strings that contain "g" are visibly shifted upward, even though all strings are uniformly ...
2
votes
0answers
74 views

Displaying primes as a 3D array of spheres

I am currently learning my way through Mathematica and have stumbled upon a strange problem. It is asking me to implement PrimeQ into ...
0
votes
0answers
42 views

problem solving a simple integral equation

I'm looking for a function q(x) so that integral( q(t) , t , x, x+2*pi/3) == a*sin(x)+b Could anyone help me on this one? Thx in advance
1
vote
0answers
59 views

How can I make my MM code more compact and readable? Can I put functions in different notebooks?

I'm doing some coding in MM9, but my program is getting quite large. It's mostly a bunch of functions defined at the beginning of it, but it's getting to the point where I have to scroll for a few ...
0
votes
0answers
40 views

How can I use a For loop in a recursive function?

I am creating a simple radix2 FFT algorithm (based on Cooley-Turkey) by using a recursive function to obtain the fft. The function is supposed to work on a list (assuming the length is a power of ...
0
votes
0answers
27 views

Calculate length of rope sound in a tight spiral [on hold]

Measuring a tightly wound spiral of rubber water tube, can I correctly calculate the
1
vote
1answer
36 views

Limit as n -> ∞ for RSolve with Multivariate Recurrence Relation

I'm trying to solve the following when n -> ∞: ...
2
votes
2answers
77 views

Automatically highlight certain cells

I am looking for a method to highlight certain cells in a table/Grid based on meeting some user defined conditions. As an example: ...
0
votes
1answer
39 views

How to efficiently distinguish the rewired edges in WattsStrogatzGraphDistribution?

The WattsStrogatzGraphDistribution function is a way to construct random graphs based on Watts and Strogatz small world model. The ...
1
vote
2answers
51 views

Unintentional function memoisation via Dynamic

I needed to display edge labels of a graph in a way that allows the edge labels to be moved. ...
0
votes
1answer
34 views

Easy NMinimize does not converge

I try to minimize the following for a>0: f[a_] := Gamma[3]*a^(-3)*(Integrate[Exp[-u]*(u - a)*1/u, {u, a, Infinity}])^(-1) I put in ...
0
votes
0answers
14 views

I have problem with Trigonometry [migrated]

Tomorrow I have a test and there is one exercise in my textbook that isn't explained. Here is the exercise. ...
0
votes
0answers
26 views

How to save all data in all variables in context different than “global”?

I have seen questions on saving data on "global" context. Now if I set my notebook's evaluation context "unique to this notebook". the global context doesn't work quite well. Any idea what should i do ...
1
vote
3answers
71 views

Initialize table in a Module but Break if criteria not met

I am initializing a table inside a function as follows: f[a1_, a2_, a3_] := Module[{RM = Table[a1+a2+a3+i1, {i1, 1, 10}]}, Plus@@RM] I am calling the function ...
-1
votes
0answers
35 views

max K-coverage problem in mathematica [on hold]

Is it possible to get a max K-coverage problem solution(s) and/or number of possible solutions in Mathematica? Additionally ...When items of subset to be must cover is given Its NP-Hard problem, but ...
0
votes
0answers
34 views

Why isn't Mathematica plotting my differential equations? [on hold]

So here are my equations eqns = {x'[t] == a*y[t] - b*x[t] + g, y'[t] == c*x[t] - d*y[t] + m, x[0] == 60937, y[0] == 13797}; Then I solved it with ...
1
vote
0answers
45 views

Summing a trig series

I am trying to sum the following expression: (Cos[(2 π m)/N]^2 Cos[(2 π n)/ N])/(2 (Cos[(2 m π)/N] - Cos[(2 n π)/N])) from ...
1
vote
1answer
38 views

expression contained across multiple cells

Is it possible to span one expression across multiple cells? E.g. long if statement or function evaluation. I looked in documentation and searched forum/google and could not find.

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