2
votes
1answer
83 views

Programmatically selecting non adjacent Cells

One can of course Ctrl + MouseClick to select 1st and 3rd cell. But how to select non adjacent Cells programmatically? I was looking for neat examples here or in ...
1
vote
1answer
208 views

How would I obtain a list of column names in a Dataset?

I really love the addition of Dataset to Mathematica. I would like to write a basic utility function that exports a Dataset to Excel. Is there a way to get a list of column names from a Dataset?
5
votes
1answer
228 views

The default ColorFunction of DensityPlot before v10?

The default ColorFunction of Plot, Plot3D before v10 is respectively mentioned here and ...
23
votes
1answer
696 views

Excessive memory use by Mathematica kernel in 10.0.2 after executing simple commands

Bug introduced in 10.0 and fixed in 10.1 Warning: the code below may hang your system if you have the Suggestions Bar enabled in Mathematica < 10.1. When issuing the following simple ...
15
votes
2answers
340 views

What is the purpose of Internal`LocalizedBlock?

I have come across the (internal) use of of the function: Internal`LocalizedBlock I am trying to determine its purpose. It seem to behave like ...
3
votes
2answers
99 views

Can GeoLabels be controlled?

I am making maps of stuff like population density and would like to add labels but GeoLabels makes it awfully busy. Here is an example. I would like to be able to control what gets written, the color, ...
2
votes
1answer
97 views

How can I make new outline cells be created above the current cell on return?

When you hit enter inside an item styled cell (e.g. Cell["", "Outline1"]), a new cell of the same type is created underneath the cell you are currently editing. ...
0
votes
0answers
50 views

“Meta-matching” patterns [duplicate]

The title refers to the general problem of writing patterns to match pattern-containing expressions (hence "meta-match"). Here's an example. In the following rules ...
1
vote
1answer
700 views

SQLSelect from Microsoft Access database tables with international character set

I am trying to import data from the Northwind (accdb) database and I have both the English and Greek versions. The problems I have are the following: 1) When I am trying to import data from ...
2
votes
1answer
282 views

Rasterized density plot with vector axes

I'm wondering if there is an easy way to get the plot below exported in a small pdf? The plot below is made in the following steps: step 1: Create a streamplot step 2: Create a densityplot, where ...
0
votes
1answer
99 views

Plotting y'[x] vs y[x] [closed]

I solved a differential equation numerically and I want to Plot y'[x] vs. y[x], but I don't know how. what is the command?
2
votes
1answer
64 views

What's the pattern that will match a head anywhere in an expression

I'm looking for the pattern patt[head] that will match any expression expr in which head occurs as a head anywhere within expr. ...
2
votes
1answer
141 views

Filtering outliers [duplicate]

I have a question. My data is: ...
1
vote
1answer
96 views
0
votes
4answers
110 views

I want to cut off secondary approximate parts

When I input to Mathematica as follows, ...
4
votes
3answers
165 views

Selective threading of the Rule

How can I change form1 to form2 form1 {10000, 10004} -> {2, 2, 637} form2 ...
2
votes
2answers
103 views

How to convert a coloured image according to the colorfunction I defined?

I got an image from a website which follows the colorfunction "Rainbow", e.g. ...
1
vote
2answers
122 views

Adding colors to objects in a loop

I'm just starting out in Mathematica and still learning the ropes. I'm making a "necklace" which is a circle with squares around it. The following works: ...
0
votes
1answer
63 views

Fastest way to make division between a number and elements in a list [duplicate]

I have a list y={{a,b},{c,d},...} of dimension {10^5, 2}, and number x. I want to divide only the second part of each element of the list by x, and have as result a new list {{a,b/x},{c,d/x},...}. ...
7
votes
0answers
125 views

One less arrow vector than asked for

Bug introduced in v10 and persisting through 10.2 or later Consider the following code: ...
2
votes
1answer
990 views

Inverse gradient operator

I found a nice paper about inverse vector operators here. I have successfully implemented a Mathematica function for most of them, however I can't figure out how to do inverse gradient (page 7 in the ...
1
vote
1answer
182 views

How to rewrite a nested loop with Reap and Sow [closed]

I was wondering if anyone know how to rewrite the following nested loop but using Reap and Sow. I need to reduce the execution time. Thank you. ...
0
votes
1answer
85 views

NMaximize against LinearProgramming [closed]

i'm starting my studies of Operational Research with Mathematica and i'm stuck on a problem with 12 variables. In fact, I was able to solve the problem using ...
0
votes
2answers
116 views

NDSolve ensemble of initial points

I want to illustrate how the differential equation depends on the initial conditions. First if all differential equations: ...
0
votes
2answers
93 views

Solving a system of two equations

I have a system of two equations with the variables T and X that I tried to solve: ...
15
votes
3answers
250 views

Partitioning with constraints on subsets

Given the following data: constraints = {{11, 2}, {11, 3}, {11, 4}, {11, 6}, {11, 9}, {1, 6}, {5, 6}, {2, 5}}; weights = {3, 7, 3, 2, 4, 2, 2, 2, 3, 2, 1}; I ...
0
votes
1answer
36 views

Relationship between input and output coefficients

This is the starting point: ...
2
votes
1answer
185 views

How can I make a map of Sierra Leone at the district level?

Hi I am trying to make a map of Sierra Leone and am running into trouble. SL has 4 provinces: Northern, Southern, Eastern, and Western, which are diced up into 14 districts as shown here: ...
5
votes
4answers
197 views

Functional way to Climb an Association Decision Tree

Associations are nice tool to create decision trees. Here is a toy example of how I'm starting to use it: ...
0
votes
1answer
35 views

Breaking term order ties [duplicate]

I am interested in creating a table with positive Gaussian integers listed in order based on their norms, with ties broken by lex order. So far I have ...
1
vote
2answers
223 views

Turn list of rules from radians to degrees, match all greek letters

Is there a easy way to match Greek letters only. I am trying to lower the angst of bachelors level students by keeping things as low level familiar as possible. Now understandably Mathematica counts ...
3
votes
0answers
124 views

PlotRange->Automatic the exact function used to calculate outliers

I know that PlotRange->Automatic does the following: "the distribution of coordinate values is found, and any points sufficiently far out in the distribution ...
1
vote
1answer
71 views

Why does TimeSeriesShift is just adding a fixed number of days?

I'd like to shift all contents of a TimeSeries object by one month. By shifting Feb. 1st I would expect to receive Mar. 1st. However it's not the case for Mathematica: ...
5
votes
2answers
415 views

Code elegance and compactness. Help needed with Map, Apply

I need some help with code optimization and compactness. I have a set of two-dimensional points and I can use the Mathematica function FindClusters to find 4 clusters. I'd like to plot the points ...
1
vote
2answers
112 views

Simplify power of KroneckerDelta

Why doesn't Mathematica simplify the following expression: FullSimplify[KroneckerDelta[x,y]^3] Since KroneckerDelta only ...
2
votes
1answer
142 views

Mathematica is able to compute an indefinite integral but not the corresponding definite one

I'm trying to compute the following definite integral (μ is a parameter): ...
3
votes
1answer
90 views

Change group generators?

I want to make Cayley graphs for the same group, but with different generators. Is there any way to represent a group, besides a cumbersome permutation representation or using the default Mathematica ...
9
votes
2answers
314 views

VectorScale Explanation

I'm having great difficulty understanding VectorScale. Here are the definitions from the documentation. With the explicit specification ...
0
votes
1answer
70 views

Weird Vectorplot

I would like to Plot a simple Vector Field, all vectors normalized to one. If i for example take a evenly distributed sample of the field and plot it with the ListVectorPlot function, i get a plot ...
13
votes
4answers
360 views

How to speed up the plotting of B-spline curve?

Three months ago, I asked a quesion about B-Spline basis function here, Today, I used this function to plot B-spline curve. The definition of $N_{i,p}$ ...
2
votes
2answers
315 views

Placing text within a plot

I want to place text within a plot. The text is always centered relative to the coordinates. How can I left-align or right-align the text relative to the coordinates? For example: ...
4
votes
1answer
138 views

DSolve not returning a rule

I am trying to solve a PDE, but the DSolve is not returning a rule. How exactly can I get Mathematica to yield a solution? ...
1
vote
1answer
84 views

TogglerBar with arbitrary dimensions

I'd like to split my TogglerBar into several rows, with it's length given in a list. I found the Appearance options, but they ...
4
votes
2answers
1k views

Image processing: Calculate the area of the region of interest

I am trying to compute the area of a particular region of interest from images which are obtained from an experiment. The original data looks like this: I have to calculate the area of the region ...
8
votes
2answers
662 views

Probability: Calculating a multiple integral

Find the value of $P[\Pi_{i=1}^{10}X_i > C]$ for $C=2,5$, where $X_{10\times 1}$ is a random vector with $10$ dimensional Cauchy Distribution having location parameter $\mu_{10\times 1} = ...
3
votes
1answer
90 views

AdjacencyMatrix: Unexpected output

I have a graph defined as follow: ...
0
votes
2answers
117 views

Finding permuations in a specific order

I would like to find the following permutations, but need an elegant way of computing it. Ideally I would like to have a variable determine the highest number in the last element and find all ...
0
votes
0answers
83 views

How to accumulate elements in a list using Reap and Sow [duplicate]

Does anybody know how to rewrite this fragment using Reap and Sow instead of AppendTo. I need to reduce the execution time. Thank you. ...
7
votes
1answer
167 views

Instant kernel crash when using `+=` on `SparseArray` with repeated entries

Bug introduced in 5.2 and fixed in 10.1.0 Not sure if this is known behavior or not, but the following two lines produce an instant kernel crash (I'm using Mathematica 10.0.1 Windows 64-bit): ...
1
vote
1answer
118 views

Fitting with roots of transcendental equation

I'm new to this community and my first question probably reflect my lack of confidence with Mathematica. My problem is the following: I find the roots of a transcendental equation dependent on a ...

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