# All Questions

268 views

### Calculating displacement for a circular disc

I have to calculate the difference in diameter of two concentric circles. The image is obtained from an experiment and the data looks like this. The length required is the value of l as marked in ...
104 views

### PNG image is exported smaller size than imported

I upload a PNG file and then split it into its red, green and blue components. I then save these components. The original image is 1440 x 764 pixels, 2.21MB. But the 3 saved files are each 360x198 ...
101 views

### How to export many images within a For-loop [duplicate]

I'm trying to export a lot of files at one time with a For-loop. I'm using ToString so I can number the output files. It's not working. Does anyone know how to ...
156 views

### Updating Manipulate output from within a Button

Consider this (edit: Pause[3] represents some long computation the button should do): ...
117 views

### Creating/placing Mathematica cells anywhere

I am interested in making powerpoint-like slides using Mathematica. The most appealing thing about writing documents in Mathematica is that it is so easy and quick to type complicated formulas with ...
349 views

### Align stars in multiple images

I hope that you find this question interesting and that this will help others with similar problems as this configuration is not so particular. My problem I have multiple images of a particular ...
138 views

### Problem with NIntegrate over a user-defined region

I define a region as follows: ...
136 views

### Perceptron: Do loop not returning a value

I am trying to write a function that finds a simple best fit line for some data (Perceptron algorithm). Sadly it returns no output at all. Here's the code below: ...
91 views

### Finding roots of a function with a varying parameter

So I'm brand new to Mathematica, and basically what I want to do is find the roots of a function at varying time intervals. The function I'm using is: ...
438 views

### How to randomly select subsets

I have a list of around 300 elements. I want to sample subsets of length 25 such that my samples are all distinct. My first inclination was to use something like ...
373 views

### Obtaining an NIntegrate error estimate

Is there a way to extract the error that Mathematica estimates when calculating a numerical integral using NIntegrate? Internally Mathematica must keep track of ...
82 views

### problems with wstp32 (WSTP / mathlink)

I've been recompiling old mathlink programs in Visual Studio 2013. No major problems so far until I got to a program that is seemingly similar to the others but that fails dramatically in the linking ...
103 views

### Unit System documentation

Is there any documentation on what consists of the unit system "SIBase","Imperial", "SI" and ...
131 views

### Saving memoization to disk

I like using memoization (i.e. the construct myFunction[x_]:=myFunction[x]=...) when I have a heavy function that I need to re-evaluate on the same arguments. ...
239 views

### Using Block with a list of variables

I have a list of variables var={v1,v2}; which I want to protect/localize during a particular operation. I have decided that I want to use ...
101 views

### Implementation of Lubaehevsky-Stillinger Algorithm to pack hard spheres

To generate a model of a polycrystalline material with specified grain size distribution (e.g coming from a Monte Carlo Grain Growth simulation) the Paper "Effects of grain size distribution and ...
165 views

### Is there a function that filter positive values x = f(x), and return zero for all negative values? [closed]

I'm searching for f that will comply this definition : x = f(x) where x is natural >= 0 0 = f(x) where x is natural < 0
224 views

### Adding map to 3D plot?

I've made a 3D plot of a pressure surface over the region 160W-20W, 20N-80N - the right panel and I would like to put a map under it, probably just continental outlines for simplicity. I'm just ...
130 views

### Problems with the plot of a function. [duplicate]

For some reason the result of Plot of the following function: ...
77 views

### Interacting Dynamic Components within LocatorPane

I am attempting to create a dynamic contour plot of an ellipse with two locators as the foci within a locator pane. The following code has been implemented: ...
83 views

### Variable change

If I have the following Hamiltonian: ...
107 views

### NIntegrate vs. summation

I' m interesting in distributions of points on sphere, plane figures etc. Especially for small number of points: 1, 3, 7, ... It seems that good criterion for uniformity of distribution is some ...
76 views

### Model without graphics

I have the next code: ...
88 views

### Export a Pyramid to VRML format

How do you export a Pyramid to vrml format in Mathematica ? I have been trying to do this the following way ...
96 views

### Slow application of Outer on a matrix

I have some performance issue with the calculation of a gaussian kernel applied to a not-that-large dataset. I'm not very good with performance tuning in Mma and I have the feeling this one could be ...
112 views

### Plot with two LabelStyle

I need to plot a graph using two different colors for the axis labels. Not working example: ...
215 views

### There is an issue with Manipulate in which it updates its argument twice in V10

I have asked this question before (here) and I thought that the issue is only when moving the Notebook window. It appears that Manipulate is working in weird manner. ...
177 views

### Export Multiple Arrays Into a Single Worksheet with Column Headers

I'm importing financial data into Mathematica, creating column headers for each array and exporting to Excel. The code below accomplishes most of this, but it creates a different worksheet for each ...
161 views

### Mysterious spikes in Plot3D

I am using Mathematica 9 and get these strange spikes when I plot the following simple function. I have seen a previous post about this but cannot figure out what is wrong with the following code. ...
68 views

### Errors when thickness is reduced solving 2D cylindrical heat conduction equation

I am trying to solve the heat conduction equation in cylindrical coordinates with a defined heat generation within the volume (a thin disk, with different heat flux BC top and bottom). The problem is ...
223 views

### How to plot on complex plane with Mandelbrot set

I essentially want to treat the Mandelbrot set plot as a normal plot so that I can plot arrows and points on top of it. This is what I want to do but it gives me an error: ...
751 views

### How to change the font color and size of tick labels by default

I've read Mike Honeychurch's answer here, and while it tells me how to change the font size on all of my plots, that size change affects (I think) all text on the plot. I would like to be able to make ...
84 views

### Are all of the numbers in my file legitimate hex numbers

I have about 10,000 hexadecimal numbers (32 digits each) in an excel file, in one column. I want to verify that all of them are indeed hexadecimal number and that no other characters are present. My ...
81 views

### Differential equations DSolve constant issue

After using DSolve to a set of differential equations, three constants arise. They are C[1], C[2] and C[21]. I have checked thoroughly that there are no C[3], C[4],....C[20]. It is quite mysterious to ...
88 views

### Strange Issue with RowBox

Can someone explain why this notebook [RANGEWORKING.nb] ...
127 views

### Output function control and manipulation for efficient computation [closed]

I have taken note of a similar post related to modifying function parameters. I tried to adapt Kuba's solution to this post but I can't get it to work. I will illustrate my problem using a similar ...
480 views

### Show plot legends for multiple curves in one plot [closed]

I have 5 curves, figure1a0, figure1a001, figure1a01, figure1ae01, and figure1ae001,. I display all these curves in one plot with Show. I want to give a label to ...
174 views

I recently set about to re-compile some old (2008-2009) applications that use MathLink in preparation for creating new, modified versions. Mathlink has been deprecated but WSTP seems like a fairly ...
1k views

### Is Mathematica ContourPlot function really so efficient?

I wanted to find the roots of the function $f(x,y)=\sin(3.2x)\sin(1.3y)-2.1 \sin(1.3x)\sin(3.2y)$. This is what the function looks like: ...
40 views

### How to evaluate NMinimize inside a function

I want to define a function that returns a sum of differences of some points to a given function. To obtain these differences I would like to use NMinimize, but if I implement that straightforwardly, ...
50 views

### Why Table is not giving me the same sequence for eigenvalues of matrix

Let consider a matrix and evaluate the time dependent eigenvalues M[t_]:={{Sin[t],Cos[t]},{t,t*t}}; e1[t_]:= Eigenvalues[M[t]] Now If I evaluate ...
338 views

### Convolution of a piecewise function

I want to find the convolute the the functions in the Convolve command ...
62 views

### Error with using SortBy in a Map [closed]

I have a data set in the following format: SomeData = {{a, 1, 2}, {b, 2, 3}, {c, 3, 4}, {b, 1, 9}, {c, 1, 10}, {a, 2, 3}, {a, 3, 8}, {b, 3, 4}, {c, 2, 9}}; The ...
187 views

### Efficient image stacking

I have a list of lists of images that I would like to stack and create mean images for each list of images. Images are .jpg files 2592x1944 pixels large. Each list ...
68 views

### Vector Analysis in Version 8

Silly question. Why does Needs["VectorAnalysis`"] Grad[Sin[x^2 + y^2], {x, y}] give the error Coordinates::invalid: "{x,y} is not a valid coordinate system ...
131 views

### Specifying WorkingPrecision in LogLogPlot produces invalid plots [duplicate]

I seem to have found a bug with LogLogPlot in Version 10. If I specify a working precision, the function produces total garbage. Here is a simple example. The first ...
213 views

### Drawing a path which realises the diameter of the graph

So I enter a (0,1) adjacency matrix and I get the following graph: The diameter of this graph is 4. How can I ask that two vertices which realise this diameter be drawn with different filling ...
257 views

129 views

### How can I copy & paste cell styles?

In Mac's mail app the key shortcut "command + option + c" gives a copy selected text style and "cmd + opt + v" pastes the style. Is there a way to achieve this with cell styles? The keyboard part is ...

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