# All Questions

39 views

### Series identity with binomial coefficients [duplicate]

I have this apparently simple equation: ...
93 views

49 views

### Unknown number of variables in a logical statement

Resolve[ ForAll[{i, y[i]}, Implies[i >= 0 && i < 3 && Implies[i < 3, y[i] > 0], Sum[y[i], {i, 0, 2}]>0]]] returns ...
30 views

### Selecting elements from a list [duplicate]

I have the following array of numbers: a = {{0, 2, 5}, {3, 5, 1}, {4, 0, 5}, {8, 3, 4}, {0, 8, 6}}; then I make a list of the first row with ...
61 views

### CDF of experimental data

Here is data.csv: ...
51 views

### Random numbers genereated from sum of multiple Gaussian distributions [on hold]

Does anyone know if it's possible using Mathematica 10 to generate random numbers from a dsitribution that is a sum of Gaussian distributions? Or if there are packages that are available that is ...
50 views

### Improve performance of processing transactions in a large file

I want to work with a table which has 296,705 transactionslines and 172,147 transactions. ...
49 views

### Getting error Import::chtype when mporting 2D array of images [on hold]

Suppose I have images = {{1.jpg, 2.jpg}, {3.jpg, 4.jpg}} Now I try to import all of them at level 2, ...
35 views

### NDSolve emitting error message NDSolve::ndnum [on hold]

I am trying to solve this system equn1 = ψ'[x] == - Elec[x] equn2 = Elec'[x] == - ((di/ a)^2)[(Exp[ψ[x]] - (x/(xoi*Sqrt[-ψ[x]])))] For that I am using ...
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### Finding a function to map one set of numbers to another on a curved line? [on hold]

I have a set of random numbers and I have to generate a new set of random numbers from these numbers. So if x represents my original number then the new number would be y. Here is what I know so far ...
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### Independence Number of Graphs [on hold]

Suppose $\alpha(G)\leq\alpha(H)$ where $G$ and $H$ are graphs, and $\alpha(.)$ is the independence number of graph. Is the following statement true? $\alpha(G\boxtimes G) \leq \alpha(H\boxtimes H)$ ...
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Thread[f[{a, b, c}, 0]] (* {f[a,0],f[b,0],f[c,0]} *) Thread[f[{a, b, c}, pp[0]]] (* {f[a,pp[0]],f[b,pp[0]],f[c,pp[0]]} *) Howerver, the head of pp ...
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### Nonlinear matrix equation solving in Mathematica

is it possible to solve below equation in Mathematica? A.X+B.Exp[X]==C A, B are square ...
83 views

### Finding minimum of a list of pairs

Sometimes I need to find the Min of a list, whose elements are lists (say of two elements, a pair). Given that Min does not have the option to indicate a sorting function like Sort, I elaborated the ...
43 views

### Table yields unexpected result [duplicate]

I evaluated Table[#[[i]] &, {i, 1, 5}] and got ...
29 views

### How to implement Wolfram|Alpha like interface in Mathematica? [on hold]

I want to write a good-looking function to calculate something. I see that WolframAlpha["gravitational acceleration"] Returns a calculation field looks good, ...
48 views

### Combine 3D plots into one with Manipulate and different region plots

The following script generates two plots in a row, both of them controlled by Manipulate. I would like to combine them together in one. The problem I don't know how to solve is that the plotting ...
30 views

### Changing Function Domain of Fourier Series

If I write FourierSinSeries[x, x, 10] Mathematica will output the first 10 terms of the Fourier Sine Series f(x) = x defined for 0 < x < Pi. How do I output the the Fourier Sine Series for ...
32 views

### How to Clear derivative definitions?

I can't find a Clear or ClearAll command that gets rid of Derivative definitions I created. this code: ...
24 views

### FindRoot[rhs==lhs, {x,x1,x2}] Vs FindRoot[rhs==lhs,{x,x1}]

What is the difference between these two commands: FindRoot[rhs==lhs, {x,x1,x2}] and FindRoot[rhs==lhs,{x,x1}] They give ...
41 views

### how to reduce noise in time series data?how to do interpolation for missing value data?

i have done this coding to plot the data. the problem is some value is missing for certain date and the graph is not smooth and noisy. one way to smooth the data is by interpolation but i dont know ...
35 views

### Solving system of equations with complex numbers [on hold]

I have two equations and two unknowns. The coefficients are complex. How do I solve them using matrices? Or any other method? Here is an example: Trying to find X and Y ...
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### Need help solving a system of 4 nonlinear equations [on hold]

Hello I'm trying to solve the following system and my computer gets stuck while trying, I've tried the Solve, NSolve an FindRoot functions all with the same result and I have no idea of what else to ...
59 views

### Performance problem with summation in Mathematica

I was trying to find out why the following function is rather slow. ...
61 views

### Como generar aleatoriamente listado de operaciones con racionales con seleccion multiple

Edit: Necesito que Mathematica me genere al azar una lista de operaciones (+,-,*,:) con numeros racionales . La cantidad de elementos de la lista asi como la dificultad de los racionales queda ...
55 views

### Removing characters from non-strings

I have a large list of lists that contains mixed data, some real, some strings. The lists are of various lengths and depths. Some of the real data values have an asterisk appended to them, e.g.: ...
35 views

### How to write ODE to standard form?

Package like odepack needs the ODE written in standard form, which means write the high order ODE to first order ODE equations. The steps of converting ODE to ...
45 views

### Packages and Notebooks as a Databin

The new Data Drop product sounds interesting. Can I use Databin to share Packages and Notebooks? If yes. How? Something like: ...
22 views

### Issue with the debug tools window

I have an issue with the debug tools window. It appears on its own periodically. I have turned it off in the Evaluation menu, and have gone to "Debugger Controls" and deselected "Show Debugger Tools ...
28 views

### Correct use of Solve inside Compile

I have a function that behaves itself, but I want to make it much faster so I tried to put it into a compilable form After much fiddling I can't get it to work. Here's one of my failed attempts: ...
47 views

### Contourplot gives inaccurate ellipses

I'm trying to draw a family of ellipses with pre-defined foci as follows: ...
77 views

### Run out of memory. How to optimize this code?

I have two sets of data: short with 22 entries, long with 46 entries. I want to take 20 entries from ...
38 views

### How to connect the front end of one raspberry pi with the kernel of another

I followed the instructions in this howto from wolfram, but I keep getting the error: ...
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### Graphics Plotfield

A number of older books use the command: <<GraphicsPlotField But Mathematica 10.0.2 says it cannot find it. Now, I know VectorPlot, but I am wondering if ...
60 views

### How do I do the Minkowski sum of two sets?

I have 2 sets, $X$ and $Y$. How do I find the Minkowski sum of these sets?
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### Draw mesh edge / map a graph to a mesh

I am doing a "force density" method to generate a mesh under certain load. The original mesh is like this: Then, I generate a IncidenceMatrix from the graph for further matrix transformation and ...
112 views

### Coloring an image with two Color schemes based on a Range

I would like to color an image generated from some data using two colorschemes based on two ranges of the data. This is my attempt. ...
149 views

### Random numbers in C++ and Mathematica gives wrong results?

I have the following strange phenomenon which puzzles me!: I have a piecewise constant probability density given as ...
35 views

### How to process Result of StringReplace?

StringReplace["item_10", "item_" ~~ x__ -> x + 1] returns "1+10" How can I force it to evaluate to 11?
54 views

### How do I create a notebook with the functionality of the Mathematica help system?

I'd like to create and distribute a notebook that functions very much like the help window that appears in Mathematica to provide documentation about functions, tutorials, and etc., but my content ...
190 views

### Real integral evaluates to imaginary number

The following integral:Integrate[Exp[-2/3 Log[1 + x^3]], {x, 0, 1}] is evaluating to an imaginary number. Its closed-form expression should be ...
48 views

### Fixed Points Problem with 2D Mapping

I have been playing with the mapping given by ...
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### Why do messages only appear first time I evaluate my compiled function?

I declare my compiled function: ...
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### Trouble using Solve and NSolve with functions involving Erf

I have the following functions: R[k_, x_, t_] := -.5*(k - x)*(1 + Erf[-(k - x)/t]) L[k_, c_, x_, t_] := .5*c*(k - x)*(1 + Erf[(k - x)/t]) I'm interested in ...
31 views

### Fourier transform of a real white noise on a 3D cubic lattice [migrated]

I'm facing the following problem: I have a cubic domain of side $L=2\pi$; this domain is divided in a cubic grid, each side is divided in $N$ points, where $N$ is an even integer number. the ...
13 views

### How do I select and open/close Input cells to prepare for printing as a document?

This is very difficult to disseminate Mathematica documents to non-Mathematica users. The input sections (with light gray background) are distracting and confusing. I want the reader to read the ...
23 views

### UnitConvert bar <-> Pa

I wanted to use the following unit cMax = Quantity[6.8221*^-9, "L/s/bar"]; But when calculating with it, I recognised there is some strange behaviour. So I tried ...
52 views

### Graphical output sizes

When outputing a list of Plots in a MatrixForm, Mathematica resizes the plots, is it possible and how to control these size reductions? Here is the typical code concerning the problem: ...
98 views

### Help going from iterative to functional

The following code segment shows what I'd like to do. I'm a procedural programmer trying to learn the Mathematica functional style. Any help on this would be appreciated. ...

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