4
votes
1answer
361 views

ListContourPlot is blocking my geometry

I have a Navier-Stokes solution for a flow past a cylinder. I have attached the DAT file. The columns in the DAT file contain the x,y,u,v,p data, respectively. The DAT file can be obtained from our ...
7
votes
2answers
837 views
17
votes
3answers
285 views

Options which require RuleDelayed

For some functions in Mathematica it is important to use RuleDelayed. One prominent example is the EvaluationMonitor for ...
38
votes
9answers
4k views

Having used Mathematica as a “gateway” language, where to from here?

I have been using Mathematica for about a year. It is the first language that I have attempted to learn. I'm still very much a newbie, but there are moments I feel more like I am waving than drowning. ...
6
votes
3answers
179 views

Is it possible to Import urls not type “”

These days I often copy urls from Internet Explorer's address bar. When I paste the url into a Mathematica cell it is neither a string nor a expression. ...
1
vote
0answers
60 views

Abridging Lists of Equations within NDSolve, Manipulate [duplicate]

I have a pretty little NDSolve function that I've finally decked out with manipulatable (by sliders) coefficients, which changes the graph in real time. However, I ...
5
votes
0answers
523 views

3D visualization of 4D object data

I have some paired data here {{x1,y1},...{x_n,y_n}} (Download link) which represents {frequency, amplitude} of a spatial object surface mesh. Its quite a lot of cells and data as you can see in the ...
8
votes
2answers
216 views

Combine InputAlias with InputString to parse expressions from a string

My knowledge of low-level notebook programming is very limited so I would be very grateful for any input regarding the following issue: I would like to define an input alias (via ...
1
vote
2answers
142 views

Converting polygon to graph in V7

I've unsuccessfully tried many ways of converting polygon points into a graph using Mathematica 7, and I am frustrated. I looked at this post, but it doesn't work: ...
8
votes
1answer
197 views

CorrelationTest small bug?

Consider two Normally distributed random variables: x1 = RandomVariate[NormalDistribution[], {1000}]; x2 = RandomVariate[NormalDistribution[], {1000}]; I want to ...
13
votes
2answers
347 views

What kind of hypergeometric function is it?

I found a formula for an integral of a product of three Bessel functions at The Wolfram Functions Site: I cannot understand what kind of hypergeometric function it is. The Mathematica code given ...
2
votes
0answers
172 views

Exporting Specific Cells of Many Workbooks into One using Mathematica

I currently have a large number of detailed files from which I would like to extract certain cells' information to make an Archive spreadsheet. There are approximately 9 parameters of each ...
27
votes
0answers
452 views

Why is StringExpression faster than RegularExpression?

Edit: as noted by Albert Retey the performance difference is only seen when sub expression extraction is performed. If this test is used below the timings are similar: ...
3
votes
2answers
220 views

Underflow occurred in compilation

This code shown below works well for n<=10, if n>11, Mathematica gives the message CompiledFunction::cfne: Numerical error encountered; proceeding with uncompiled evaluation. >>. So ...
33
votes
2answers
627 views

How safe is the use of Block and Internal`InheritedBlock

For many questions on this site answers are given which suggest to use Block and, especially for more advanced topics, ...
1
vote
0answers
118 views

How can I say that all quantities need to be positive (and real)? [duplicate]

Can you say at the beginning of a script in Mathematica that you want all the quantities to be positive (and real)? So that in all calculations, only the real values of these quantities will be ...
2
votes
1answer
271 views

Simple problem about shadow symbols in multi-contexts

When I'm tiding up my simple packages, shadow awlays comes out. Here is an example. Packages1 ...
2
votes
1answer
205 views

Emulate Powerpoint behavior: Show additional cell content with each click

Is it possible to emulate powerpoint animation behavior during a presentation with Mathematica? Considering a notebook with cell of numbered items or even several cells, is it possible to display a ...
3
votes
1answer
138 views
0
votes
1answer
62 views

Have the kernel load a user-defined function by default [duplicate]

I wrote a very simple function that I would like to act as if it were one of the default functions that came with Mathematica, so that you don't have to load or import any package before you make use ...
1
vote
2answers
927 views

Plot 3D set (or a domain of three-variable function)

is there any way to plot a "3D set" of points subject to certain rules? For example, my task is to find maximum of some function of three variables which have to meet some conditions. Of course I ...
7
votes
2answers
256 views

How to replace a variable that was assigned a value before

Question How to make the replacement $f[x] \to f[y]$ for an abitrary function $f$ if $x$ was assigned a value before? Example 1 How can I make the replacement $x +1 \to y + 1$ if I have assigned ...
3
votes
0answers
60 views

How to generate absolute Directories in HTML

...
14
votes
4answers
983 views

Combine absolute and relative (scaled) coordinates

I am using Inset to add an Epilog to a plot. The position of the images (in my case: framed numbers) can be specified as an ...
1
vote
1answer
1k views

Using NonlinearModelFit to fit data with errors

Assume we have some data of measurements SeedRandom[9]; data = Table[{i,2*(1 + 5*RandomReal[])*Exp[-0.01*(1 + RandomReal[])*i]}, {i, {0, 100, 200, 400, 700}}]; ...
5
votes
1answer
74 views

How to relate memory usage with occupied positions of SparseArrays?

What is the relation of memory usage of a SparseArray and the number of its occupied positions? Let's say you build a 100.000.000 by 10 element SparseArray. And fill the two position 1/1 and ...
4
votes
4answers
271 views

Filling and Shading an Harmonic Curve

Suppose I have an equation plotted as shown: ...
5
votes
0answers
84 views

Faster way to perform SameQ[Reduce[…], Reduce[…]]

I'm have some expressions that I need to confirm the equality of. SameQ[Reduce[...], Reduce[...]] works like a charm for the more simple expressions, however when ...
0
votes
1answer
128 views

Interpolation and points of non-differentiability

I have some data, which if expressed by some elementary functions, would contain a non-differentiable point. I would like to be able to use something like interpolate to convert the data into a ...
2
votes
2answers
271 views

Optimizing functions taking matrix arguments

I'm looking for general information on how to optimize matrix valued functions, I have the following function I'm looking to maximize (or figure out if this is possible at all). ...
8
votes
2answers
315 views

How to draw a contour diagram in Mathematica?

This answer at Math.SE contains a neat contour diagram created using Mathematica: What Mathematica functions I can use to draw diagrams like this?
8
votes
2answers
324 views

Telling mathematica to output * instead of space for multiplication, so I can copy as plain text

I am trying to get some symbolic expressions in Mathematica which I would like to paste into my C/MATLAB codes. This can be accomplished nicely by selecting the expression and right-clicking to ...
4
votes
5answers
258 views

A simple StringCases problem

Given this text: text1 = " A Vitamin D Deficiency (ICD-9-CM 268.9) (ICD-9-CM 268.9) 09/11/2015 01 "; Yes, the ICD code values are duplicates- possibly but ...
9
votes
1answer
249 views

Performance of Dispatch and lists of Rules

The issue outlined here seems to be no longer present in version 10, if you use a Dispatch table! This because a Dispatch table ...
4
votes
1answer
91 views

Question about usage of Style as Dynamic object

I saw a Dynamic snippet in this answer, which wrote ...
0
votes
0answers
53 views

Question regarding function definition overloading / argument passing test [duplicate]

It is possible to define function dependently to passed argument type or condition this argument fulfills (somewhat like overloading): ...
1
vote
1answer
374 views

Weird vertical line when trying to plot a histogram [duplicate]

I'm trying to plot a histogram of a few data points and overlay a plot on it (it's a fit of a geometric distribution to my data). The weird thing is that a vertical line appears always next to the ...
2
votes
1answer
158 views

How to draw tiles with different height?

I have a random matrix RandomReal[{1, 2}, {20, 20}], whose elements represent the heights of an array of tiles. The cross sections of each tile are square and ...
6
votes
2answers
672 views

Manipulating plot of random iterated function system fractal

I'm generating the Sierpinski Gasket by implementing a chaos game in mathematica. What I'd like to do is create an interactive manipulation with a slider, whereby moving it forward, plots all the ...
1
vote
0answers
124 views

FindRoot runs out of memory in Windows but not on Mac

I am using FindRoot to find solutions to a large, highly oscillatory equation which I generated using other code. When I run ...
3
votes
1answer
128 views

Filtering the elements of an array to split them into two categories

So, I am new to Mathematica, and I am trying to write something that involves taking values from one array and separating them into two different arrays. My code for doing this is: ...
0
votes
0answers
110 views

Precision of a complex number

In an output I'm getting a number like -0.33998187034939803 + 0.I. Finding ...
6
votes
1answer
109 views

create function that behaves like continuedFraction [duplicate]

I'm just starting to learn Mathematica and I got stuck at this question. This a noob question but please help. I need to define a function named continuedFraction that takes user input of type list ...
29
votes
5answers
928 views

Why is there no PositionFunction in Mathematica?

Too often I have seen the programs of inexperienced users greatly slowed by using Position in an iterative fashion, when far faster would have been to compute a ...
20
votes
4answers
2k views

How can I detect an ellipse in a photo?

I tried to detect the rim of the following cup as an ellipse. I've tried the solutions given in How to find circular objects in an image? to detect the ellipse, but the detection result was not ...
3
votes
1answer
169 views

How can I use Manipulate[] to click on a Graphics3D output and generate $(x,y)$ outputs on a projection plane parallel to my screen?

Say I have some Graphics3D object that I'm looking at from a top down perspective, e.g.: ...
0
votes
0answers
27 views

How do I automatically “trim” the bounding box for a Graphics3D output? [duplicate]

I noticed that, provided some Graphics3D output scaled with ImageSize, I can get rid of a lot of the empty space around the graphic by right-clicking and then selecting "Trim Bounding Box". Thinking ...
6
votes
1answer
196 views

undisputed FrontEndTokenExecute

Thanks to this great topic, I've found the FrontEndToken that I was looking for: "DeleteGeneratedCells" (well, it is also ...
2
votes
1answer
138 views

How to keep ItemSize effect when export to HTML

Here's the simple code Grid[Table[Item[1,ItemSize->{5,10}],{2},{2}],ItemSize->{5,10},Background->Red] After saving the output cell as .html file, ...
2
votes
0answers
168 views

Speeding up a numerical constrained quadratic optimization

I'm trying to solve a quadratic optimization problem in 35 variables, $\vec{α} = \left< α_1, \ldots, α_{35}\right>$: $$ \begin{aligned} &\operatorname*{maximize}_\vec{α}&&1.0\cdot ...

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