# All Questions

42 views

### Join a surface and a density plot [duplicate]

My question is if it's possible to do something like this with Mathematica: I know that it is possible to plot a surface with Plot3D and a 2D plot with DensityPlot, so I was wondering how to join ...
286 views

### Replacing parts of a matrix

I'm a beginner to Mathematica and to writing scripts in general. I'm currently trying to write a code that will take any element in a matrix higher than a certain threshold value n and set it equal to ...
101 views

### Products of Differential Operators

I have a differential equation defined as the product of operators which I want to expand out into a polynomial in powers of $z\frac{d}{dz}$ $\qquad \prod_{n=1}^p(z\frac{d}{dz}+a_n)$ However when I ...
204 views

### Append new data to excel?

From this post I know that I can export my data from mma into any given position (such as "B3"), but now I want to append new data to the old one. As an example, ...
70 views

### Incomplete Parallel Mapping

I am still struggling on how to nicely handle list operations in Mathematica, and perform simultaneously parallel computation. We consider a tab of the form ...
857 views

### Import a given column from an excel file? [closed]

It seems that I can get the first column of excle data, say "test.xls", if I know the total length... ...
162 views

### BUG: Problems generating FEM ElementMesh in 1-D

fixed in 10.1 (windows) I'm trying to build an ElementMesh for a simple 1-D problem. First, I build the boundary ...
353 views

### How to convert a Mathematica list in a Python list?

I was wondering if you know, how to save a Mathematica list (variable) such that it can be read later in Python. In order words, how to save a variable ...
278 views

### I need some GPU benchmark for Mathematica [closed]

I am considering to buy a GPU. I need to know two things: Is it possible to solve a system of differential equations using GPU and Mathematica's functions? I need to know how much faster would be ...
138 views

### What is the largest system of PDE you have solved with Mathematica? [closed]

I need to solve a system of partial differential equations. In the simplest case it consists of 2000 of PDE equations. In the most complex situation it consists up to 1 million of such equations. ...
122 views

### Calculate this integral returns undefined

Limit[ (Integrate[Sqrt[Exp[3 t + 2] + 3] , {t, 0, x}]^2) / Integrate[Sqrt[Exp[6 t - 2] + 5] , {t, 0, x}] , x -> Infinity] This can be solved but ...
77 views

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267 views

### How to write markdown with Mathematica?

Usually I typeset with Latex and Compute with Mathematica and then copy the outputs as Latex code and insert them in Latex, so I have to switch between Latex and Mathematica frequently. Thanks to the ...
70 views

### Integration of an expression yields wrong result

I'm trying to find a general expression for the definite integral of ...
62 views

### How to get an elements of given class that generated by javascripts

I want to get the number of total pages of a given search resluts of this site: http://srh.bankofchina.com/search/whpj/searchen.jsp, e.g., from 2015-1-12 to 2015-1-13 the currency of USD by the ...
367 views

### Importing numbers from Excel

I guess my problem is very simple but I could not find the solution by searching it. I have a column in excel sheet (Sheet1 in Book1.xlsx) including student numbers as the following. ...
140 views

### Json response for Nodejs with webMathematica

I am trying to pass RESTful calls from my Nodejs server application to webMathematica. How to do so? I also want to receive the response as JSON.
216 views

### How can I download a tweeted image given the tweet id?

ServiceExecute[] supports sending an image via "ImageTweet" i.e. posting an image in a tweet. But how can I achieve the reverse of this and download the image given ...
97 views

### Why do PopupMenus render inconsistently on Macs?

This has been bugging me for years but because it doesn't effect performance I've never got around to asking. The problem below occurs for me in V8, 9, 10 with OS X 10.8, 10.9 and 10.10. I've tested ...
150 views

### Extracting an equation from an interpolated function

Im trying to use LibraryLink to do some calculations in C but part of the expression i want to calculate is an Interpolating Function. C cant use that obviously so I'm trying to shift it to a data ...
129 views

### Very poor subpixel antialiasing using rotated monitor

I use Mathematica 10 for Linux with my monitor rotated 90-degrees. Fonts in all applications look very good (I have configured Gnome and Xft to do subpixel antialiasing in "vertical RGB" order). But ...
79 views

### Series with specific notation

I'm trying to get mathematicas series function to output a result that look like this: instead of calculating the actual "values", like doing so here: ...
585 views

### The longest run of at most k different elements in a list

I have a long list with ca. 500K elements. The list contains about 10K different elements. For simplicity let’s assume the list is of the following form: ...
193 views

### Can GPU (CUDA) speed up LinearSolve?

Is there a way to use GPU (CUDA) to speed up LinearSolve?
230 views

### Distinguishing left from right adjacent triangles in triangle mesh [closed]

What I'm trying to do: I'm trying to create a path-drawing function which will produce a path like the one I-P in the diagram below. The way this path was generated requires me to swap between the ...
355 views

### Extracting intensity from an image

Suppose I have an image sampleOriginal = Import["...mySample.png"] I then convert it to Grayscale colorspace ...
127 views

### LinearModelFit - Number of unique basis functions & Invalid variable errors

I'm having trouble with a simple linear fit model. Here is my code ...
2k views

### How to calculate extremely large exponential

I would like to calculate the following nested exponential: $$\Large{e^{e^{10^{72}}}}$$ In case that might be hard to read, in Mathematica functional notation it is: ...
187 views

### How can you resize all the images in a notebook section?

I've pasted a large number of photos and they are too big which makes scrolling hard. Is there a way to automatically have Mathematica size them to 10% or something reasonable without have to click on ...
715 views

### How to train a convolutional neural net on images?

The functions Predict[] and Classify[] both have the option Method -> "NeuralNetwork", ...
235 views

### Explicit digit-count (precision) of real number

I'm trying to do something which seems like it should be simpler than it is (at least in my attempts at it). I have some code where I read in a list of numbers generated for me by a coworker. These ...
65 views

### AdjacencyList of DirectedEdges in Graph ignore edge direction

I have a simple tree graph with directed edges: In: AdjacencyList[Graph[{a -> b, a -> c, b -> d, b -> e}], b] Out: {a, d, e} I wonder how I can ...
186 views

### How to understand the difference between Sqrt and Log after ClearAll them

I came across this post, here I change the last line of the code Unprotect[Sqrt]; Sqrt[x_] = "blahblah"; Protect[Sqrt]; Sqrt[2] "blahblah" ...
63 views

### Plot of the set complex numbers [duplicate]

I want to show this set (eigenvalues of my matrix): ...
129 views

### ListPlot3D keeps crashing

I have some data, and I want to plot it by ListPlot3D: ...
29 views

### 'MatrixForm' problem [duplicate]

I prefer to use 'MatrixForm' because the form looks better in matrix manipulation. But my current problem is that after the use of 'MatrixForm', subsequent matrix calculations like 'Det' or 'Inverse' ...
162 views

### Calculate efficiently an expensive hermitian matrix

I want to compute a matrix $M_{pq}$, for which the calculation of each coefficients $M_{pq} = f(p,q)$ is an expensive function. I know that my matrix is hermitian, so that $M_{qp} = M_{pq}^{*}$. As a ...
108 views

### How to speed up my code with constructing matrices

I have run this program for a long time to get the result for n = 2048(about 5hours) and no more result till now (can't run with n = 4096). I would know how to make it more efficient. Any help or ...
313 views

### Check whether array has only constant entries?

I have an array arr with n entries. Now I want to check whether ...
149 views

### Problem using Position applied on matrix with Infinity elements

Am I doing something wrong here? ...
224 views

### Finding the Position of the Minimum Neighbor for Each Element in a Large Matrix

I have a large matrix ($6020\times 8452$), and I want to create a new matrix where the relative position of the minimum neighbor is each element in the matrix. For example, if I had the matrix ...
278 views

### mathematica 10 not showing numerical solution of differential equations?

I just got the new mathematica version 10 and tried to solve the following system of differential equation. $$r^2\frac{d^2f}{dr^2} = 2f(1-f)(1-2f)+\frac{r^2}{4}h^2(f-1)$$ ...
106 views

### Option: number of digits

The command NestList[Cos, 1.5, 10] produces the list: ...
96 views

184 views

### Operations on transfer function model

Suppose I have a transfer function defined via TransferFunctionModel, e.g. tf == TransferFunctionModel[{{1/s}}, s]. How can I ...
314 views

### Building Butterworth Bandpass Filters

In order to bandpass filter data it is necessary to use ButterworthFilterModel, followed by ToDiscreteTimeModel and RecurrenceFilter. I have two questions: I wish to specify the order of the ...
64 views

### How make first automatic numbering cell for a style number 1 not 0?

I have a cell style "Figure" for a notebook, defined as: Cell[StyleData["Figure", StyleDefinitions -> StyleData["Text"]], MenuSortingValue->10000] In ...
174 views

### Showing steps for TrigExpand

If I enter a double equal sign and the following in Mathematica 10: == integrate 1/(1+x^4) Then wolfram alpha allows me to select a Step-by-step solution, which ...