1
vote
1answer
169 views

direct assignment to the element in a Table

I have already asked a related question here why set values in this way doesn't work? But I think I have to write the question which I encountered explicitly? ...
1
vote
2answers
269 views

How to blend some colors on a curve

I need to define a color gradient on a 3D curve, but I'm having some problems with this. Suppose we have a 3D curve defined as a parametric function of some real variable ...
1
vote
1answer
969 views

Add noise (random values) to data

I have a data set(x,y,z) corresponding to a hemisphere, to which I want to add some controlled noise (random values) to make the x,y,z values diverge. data = Flatten[ Table[{i, j, i^2 + j^2}, {i, ...
1
vote
1answer
918 views

How to set path of IMPORT from excel into Mathematica?

I was able to IMPORT from excel data at the start of my project when both the .nb and EXCEL XLS files were sitting in MyDocument (or some other location), but upon moving both files into my Dropbox ...
1
vote
1answer
1k views

Adjusting the legend colors to match that in MatrixPlot

I am trying to show the legend with a ColorData for a discrete Fourier transform coefficient table. Here's a sample data table: ...
1
vote
1answer
639 views

Using previous two solutions as a start point in FindRoot

I need to solve a sequence of equations and I want the starting point of each new FindRoot to be the solution of the earlier FindRoot, increased or decreased by a a bit in the following way: Some ...
0
votes
0answers
61 views

Improving semantic interpretation of dates

SemanticInterpretation and Interpreter are promising but imperfect, eg extracting dates and calendar expressions from ...
0
votes
1answer
103 views

PDE of real-world system, integral boundary condition

I've stripped all the physical-significance for clarity, but I know that u[x,t] will be everywhere positive and continuous. here are the equations in Mathematica code: ...
0
votes
2answers
106 views

What is wrong with combining two programs with event handlers?

I can delete the unwanted nodes of a RandomGraph by double-clicking on them from the first program, and I can change the positions of the nodes by dragging them ...
0
votes
1answer
371 views

How to use `FindRoot` to solve an equation containing a parameter?

I'm trying to derive some of the results of the following paper: Electrodynamics of semiconductor-coated noble metal nanoshells, JT Manassah - Physical Review A In the paper there is matrix $\mathbf ...
0
votes
1answer
153 views

iterative programming

i have 3 equations with 3 variables and two constants(to be substituted repeatedly). the value of the variables we got by applying nsolve on the system of 3 equations assuming some initial value for ...
0
votes
1answer
346 views

Function to marginalize a table over given parameters

Let us say I have generated a table tab with entries {p1,..,pd,chi2[p1,..,pd]} of dimension ...
0
votes
1answer
179 views

TextRecognize with crosses, circles and spaces results into oddities, why?

I am investigating this answer here about detecting crosses and circles with TextRecognize. I tried to solve this problem here by directly using the builtin command TextRecognize but it does not work ...
0
votes
2answers
593 views

Using Mathematica to find poles of Gamma functions

I am concerned about the expression on the RHS of equation A.5 (page 19) in this paper: $$\int\frac{d^d ...
0
votes
1answer
576 views

Solving Differential Equation depending on variables solved by NDSolve

How to solve a differential equation which consists of variables depending upon another differential equation?
14
votes
0answers
202 views

Why is ListPlot so slow here?

While examining How can I monitor the progress of a Plot? I was surprised to discover that in some cases ListPlot in version 10.0 and 10.1 is orders of magnitude ...
14
votes
1answer
215 views

Why won't SparseArray let me store values with the head List?

When you attempt to define a SparseArray with elements that have the head List it complains: ...
14
votes
4answers
930 views

What does DisplayFunction->Identity do to graphics functions?

Does DisplayFunction->Identity do anything at all in Mathematica 8? In the third edition of Programming in Mathematica, Roman Maeder gives the following ...
13
votes
2answers
255 views

Weird behaviour when using Scale, Rotate in Graphics

Bug persisting through 10.2.0 (Edited to simplify drawing) I have a drawing of two tangent circles: ...
13
votes
1answer
406 views

Greek variables in 10.0.1

Bug introduced in 10.0.1 and fixed in 10.0.2 10.0.1 under Ubuntu 12.04 x64 .... Does everybody get greek variables emboldened? Is anybody aware of how to revert to previous normal display? The ...
13
votes
1answer
361 views

Just what kind of transformations can TransformedDistribution handle?

Why does the following command return an empty plot? ...
13
votes
4answers
3k views

How do I draw a DensityPlot in polar coordinates?

I am trying to plot $J_m(\chi_{mn} r) \cos(m\phi),$ where $J_m(\chi_{mn}) =0,$ as a DensityPlot in polar coordinates (solution to 2D wave equation in polar ...
12
votes
1answer
251 views

AbsoluteOptions prints error messages in V10

Bug introduced in 10.0.0 and fixed in 10.0.2 I am trying to use AbsoluteOptions in V10 but I am getting the Out with some errors as see in this picture: does anyone have same issue?
12
votes
4answers
534 views

Why is Poisson Random Deviate Generation so slow?

I am generating Poisson deviates for some numerical work. Mathematica 9.0.1 is very slow in generating these random numbers, as can be seen below. ...
12
votes
5answers
1k views

Sort date list in format DD/MM/YYYY

I have a list of dates (ranging from 2007 to 2012) in the DD/MM/YYYY format and I need to sort this list. My problem is, when I simply use Sort[] I get: ...
12
votes
4answers
515 views

Grid - Item - Alignment to decimal problem

Still present in version 10. I've run into a Grid layout problem for which I don't know a solution. I want to specify alignment to a specific character such as ...
12
votes
3answers
451 views

Arguments to If[] are not evaluated

I got bitten by the following: f[x_] := 3*x; g[x_] := If[Log[f[x]] < 0, f[x], 0]; g[x] Out[11]= If[Log[3 x] < 0, f[x], 0] where I thought the call to ...
12
votes
1answer
343 views

Are there rules of thumb for knowing when RandomVariate is more efficient than RandomReal?

Please consider the following: From a fresh Mathematica kernel, RandomVariate is more efficient for NormalDistribution but ...
11
votes
1answer
261 views

What is the default ColorFunction for Image3D?

What is the default ColorFunction for Image3D? I find it a bit confusing that the most intense colour is not shown where the ...
11
votes
1answer
251 views

Where is my memory? — LibraryLink never returns the memory

Bug introduced in 8.0 or earlier and persisting through 10.2.0 This is an example LibaryLink code from Mathematica documentation, which takes an integer and return an integer list: ...
11
votes
2answers
870 views

Why does this simple program leak memory?

I have a simple Mathematica program which writes some plots to image files for later conversion into a movie. Unfortunately, the program leaks so much memory that it quickly exhausts all 12G of RAM ...
11
votes
5answers
717 views

How to plot rectangles aligned by their center?

Supose I have a rectangle which area is $x^2$. In some cases I may not know what is the size of each side, for $x=12,$ we have several possibilites: ...
11
votes
1answer
824 views

What is the fastest way to find an integer-valued row echelon form for a matrix with integer entries?

Let me begin by saying that this is my first post on StackExchange. I apologize in advance if I unwittingly break any of its unwritten rules of etiquette. Recently, I've been trying to understand an ...
10
votes
3answers
401 views

Combining many plots with Show produces wrong x-axis position and wrong filling

The code is as follows, ...
10
votes
4answers
306 views

Why do quote marks appear in output when saved with Save Selection As?

Update #2: This behavior has been confirm across platforms and in multiple versions. Therefore: Is this a bug or a feature? Can I disable this "feature" so that copying a selection of Cell contents ...
10
votes
0answers
245 views

Setting non-standard ImageResolution for EMF export as default

Mathematica has a bug in that BarCharts and ListPlots with Filling will export as a ...
10
votes
2answers
734 views

Derivative from the left and right

I am currently trying to write a script that takes a curve $C$, a starting point $p$ and a direction vector $\vec{v}$ and calculates the path of a beam starting at $p$ in direction $\vec{v}$ when it ...
10
votes
2answers
171 views

GridBox/packed array behaviour

I have never used low-level formating functions, so this problem might have a simple solution. I'm currently pulling my hair out trying to solve it, however. Consider the following example: ...
9
votes
1answer
385 views

Nintegrate has memory leak

Bug introduced in 6.0 and fixed in 10.2.0 NIntegrates uses memory and does not release it. For long loops with NIntegrate ...
9
votes
1answer
254 views

Did 10.0.2 break some forms for named slots?

Bug introduced in 10.0.2 and fixed in 10.2.0 Since 10.0.2 some code that previously worked using named slots fail in very particular circumstances. Attchd screenshot shows the issue w/ a ...
9
votes
1answer
445 views

Oval or Bunimovich stadium

The dynamic billiard demonstration, that can be found on wolfram demonstrations (here), is only designed for an ellipsoid-shape boundary(snapshot below). The idea is to have a dynamic billiard with ...
9
votes
1answer
248 views

How to define function that can change patterns

Given time series data as follows: data = {{{2011, 1, 13}, 10}, {{2011, 2, 14}, 17}, {{2011, 3, 15}, 20}, {{2012, 1, 16}, 30}, {{2012, 2, 17}, 40}}; ...
9
votes
6answers
427 views

Performing Computations on Sets

I would like to find a permutation of $\quad S=\{\frac{1}{10}, \frac{1}{2}, \frac{4}{7}, \frac{3}{5}, \frac{2}{3} \}\quad$ that maximizes the sum of theses elements raised to unique powers: ...
9
votes
2answers
755 views

Interpolation of mostly-structured 3D data

this question relates to interpolation of 3D data and Improved interpolation of mostly-structured 3d data I have an irregular 3d data set that is quite large (around 70,000 triplets---let's call it ...
9
votes
2answers
519 views

Image of input and output cells is not exported correctly

Wolfram Blog uses PNG images to display input and output cells in a notebook. For example, the following is an image from Samuel Chen's post: I should be able to produce a similar image by ...
9
votes
2answers
705 views

Why is JLink loaded every time I start Mathematica?

When I start a Mathematica 8 session (either command line or with the notebook front end), I notice that there are several packages that have already been loaded for me (using ...
8
votes
1answer
179 views

SymplecticPartitionedRungeKutta shows strange error

Bug introduced in 9.0 or earlier and persisting through 10.2 or later I tried to solve Hamiltonian system ($Q$ is a vector of all generalized coordinates, $P$ - of generalized momentum) $$ ...
8
votes
2answers
145 views

SetOptions for CoordinatesToolOptions for DateListPlot?

Bug introduced in 10.0 and persisting through 10.2.0 or later DateListPlot does not respect my Options setting for ...
8
votes
1answer
234 views

Why don't products of Dirac deltas integrate correctly?

Bug introduced in 10.0.0 and fixed in 10.0.1 The integral $\int \int \ \delta(x) \delta(y) \ dx dy=1$ evaluates to 0 in Mathematica ...
8
votes
2answers
273 views

Unexpected behavior when using SortBy as a dataset filter

I am still experimenting with datasets. Recently I tried to query the Titanic example to get info on the oldest passengers. Here is what I tried ...

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