# All Questions

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 ...
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) ...
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 ...
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 ...
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 ...
74 views

### Undocumented form for Extract

Prompted by a comments conversation here, here's an interesting (and often performance enhancing) use of Extract: ...
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 ...
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 ...
26 views

### A problem with set values

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

### Solving nonlinear system by newton method [on hold]

How to solve nonlinear system by newton method (without Findroot method)? What is algorithm?
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 ...
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 ...
91 views

### Scan vs Map vs Apply

I cannot understand the difference between Apply, Scan, and Map. I have tried to play with ...
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?
35 views

### solving simple integral equation [on hold]

Could someone help me finding q(t) so that $$\int_x^{x+2\pi/3}q(t)\,\mathrm{d}t = a\cdot\sin{(x)}+b$$ Thanks in advance!
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 ...
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 ...
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 ...
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 ...
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 ...
31 views

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 ...
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 ...
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 ...
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
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 ...
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 ...
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
36 views

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

I'm trying to solve the following when n -> ∞: ...
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: ...
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 ...
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. ...
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 ...
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. ...
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 ...
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 ...
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 ...
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 ...