1
vote
0answers
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 ...
5
votes
4answers
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 ...
4
votes
1answer
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 ...
1
vote
0answers
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, ...
1
vote
2answers
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 ...
0
votes
2answers
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... ...
3
votes
2answers
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 ...
0
votes
1answer
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 ...
1
vote
0answers
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 ...
0
votes
0answers
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. ...
0
votes
3answers
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 ...
0
votes
1answer
77 views

Scaled Point in Graphics3D

...
8
votes
0answers
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 ...
0
votes
1answer
70 views

Integration of an expression yields wrong result

I'm trying to find a general expression for the definite integral of ...
0
votes
1answer
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 ...
1
vote
2answers
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. ...
1
vote
0answers
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.
6
votes
1answer
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 ...
3
votes
0answers
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 ...
3
votes
0answers
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 ...
5
votes
0answers
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 ...
1
vote
2answers
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: ...
10
votes
6answers
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: ...
1
vote
0answers
193 views

Can GPU (CUDA) speed up LinearSolve?

Is there a way to use GPU (CUDA) to speed up LinearSolve?
2
votes
1answer
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 ...
1
vote
2answers
355 views

Extracting intensity from an image

Suppose I have an image sampleOriginal = Import["...mySample.png"] I then convert it to Grayscale colorspace ...
0
votes
1answer
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 ...
4
votes
2answers
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: ...
6
votes
2answers
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 ...
10
votes
1answer
715 views

How to train a convolutional neural net on images?

The functions Predict[] and Classify[] both have the option Method -> "NeuralNetwork", ...
4
votes
2answers
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 ...
3
votes
1answer
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 ...
5
votes
1answer
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" ...
0
votes
1answer
63 views

Plot of the set complex numbers [duplicate]

I want to show this set (eigenvalues of my matrix): ...
1
vote
0answers
129 views

ListPlot3D keeps crashing

I have some data, and I want to plot it by ListPlot3D: ...
0
votes
0answers
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' ...
3
votes
1answer
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 ...
0
votes
0answers
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 ...
4
votes
5answers
313 views

Check whether array has only constant entries?

I have an array arr with n entries. Now I want to check whether ...
2
votes
2answers
149 views

Problem using Position applied on matrix with Infinity elements

Am I doing something wrong here? ...
4
votes
2answers
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 ...
7
votes
1answer
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. $$r^2\frac{d^2f}{dr^2} = 2f(1-f)(1-2f)+\frac{r^2}{4}h^2(f-1)$$ ...
1
vote
1answer
106 views

Option: number of digits

The command NestList[Cos, 1.5, 10] produces the list: ...
5
votes
1answer
96 views

How can I make 1+$MachineEpsilon not look like 1?

I undarstand that 1+$MachineEpsilon is actually not equal 1. However, it persists to look like it was equal ...
1
vote
2answers
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 ...
7
votes
2answers
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 ...
0
votes
1answer
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 ...
2
votes
2answers
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 ...
1
vote
0answers
51 views

Complex input for Compile makes it slow

I asked a question here and then tried to use Compile for the solution to gain even more speed. Inside Compile there is a loop ...
2
votes
1answer
120 views

How get repeated elements from two lists

How to write a code that takes an certain element related to a given subset in a LIST 2, that occurs also in a LIST 1? for example, there are two lists: ...

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