0
votes
1answer
248 views

Projection of a set of 4D points to the 3D space

Consider the following set of points in the 4D space: ...
7
votes
4answers
428 views

Counting multiplications (complexity function)

I'm trying to count the number of times multiplication appears in an expression (for the purpose of constructing a ComplexityFunction that would help me simplify a terrible algebraic expression for ...
24
votes
7answers
3k views

Embed Code Into Image

I often export images(plots, matrix, arrays, etc..) from mathematica which I end up putting in word documents or uploading to the web. The problem is that I often lose the original code and I am left ...
1
vote
0answers
80 views

Is the TCPIP link type compressed?

Since I'm already piping a MathLink connection in a ssh tunnel (connect back is a pain!), I wonder if it makes sense to compress the data in the stream (ssh -C). As ...
3
votes
2answers
221 views

Explicit asterisk or @ sign in string patterns

What string pattern will match an explicit asterisk (*) or at-sign (@)? The obvious example, StringMatchQ["*", "\*"], returns ...
2
votes
2answers
197 views

Finding integral points on a surface

Suppose I have a dimension formula (for a Lie algebra representation) that is as follows: $$ d(a,b) = {(a+1)(b+1)(a+b+2) \over 2} $$ Now consider the surface $F(a,b,n) = 0 = d(a,b) -n$ where $n \in ...
2
votes
2answers
384 views

Mapping multiple functions

This question was part of a course on Mathematica written in 1998. Each of the functions f1, f2, and f3 defined below has a root near x=2. Map an anonymous function involving FindRoot[] onto ...
1
vote
0answers
60 views

Sorting Eigensystems [duplicate]

SO I have this code: ...
11
votes
3answers
939 views

Every second evaluation in notebook front end is slow

I'm having a rather baffling problem that Wolfram was unable to help me diagnose, and I'm hoping one of you geniuses in residence here can figure it out. (I don't get access to the Technical Support ...
1
vote
3answers
421 views

Making a calculation with high precision

I would like to make the following calculation: 1/Sqrt[1 - (150^2 10^(-4))/(9 10^16.)] - 1 Mathematica 8 returns 0. The result is obviously not 0, but my ...
6
votes
2answers
309 views

Is it possible to import data from Google Analytics?

Using Mathematica, is it possible to pull data directly from Google Analytics? Unfortunately, GA exports messy csv files, and I was wondering if there was a direct ...
2
votes
2answers
950 views

Forecast Future Stock Prices - Brownian Motion - Again

excuse me, I think I have here a technical problem with Mathematica yesterday I posted the question with the title: Forecast Future Stock Prices - Brownian Motion I am still not very experienced but ...
4
votes
1answer
208 views

String encoding issue with Pythonika

I use Mathematica and Pythonika to run Python code inside it. And I'm not quite sure what causes my issue: all unicode Python objects look like this: ...
3
votes
1answer
86 views

Some _atomic elements' TreeForm looks confusing with Level in appearance

In[1]:= Level[1/2,{-1}] Out[1]= {1/2} TreeForm[1/2] ...
3
votes
3answers
206 views

Plot sublists as different colors

I have one big list with many sublists inside. All sublists consist of three numbers. For example: ...
2
votes
1answer
60 views

Does a manipulation of a plot area produce new data?

You do a ListPlot. Plot[Sin[x^2], {x, 0, 1}] pdat1 = With[{fig = Plot[Sin[x^2], {x, 0, 1}]}, First@Cases[fig, Line[x_] :> x, Infinity]]; You ...
4
votes
1answer
206 views

How to extend dictionary.txt

How to extend the default dictionary.txt for Dictionarylookup to all words? For example, first I ...
4
votes
1answer
540 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
1k views
18
votes
3answers
306 views

Options which require RuleDelayed

For some functions in Mathematica it is important to use RuleDelayed. One prominent example is the EvaluationMonitor for ...
43
votes
10answers
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
186 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
61 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
621 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
227 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
149 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
207 views

CorrelationTest small bug?

Consider two Normally distributed random variables: x1 = RandomVariate[NormalDistribution[], {1000}]; x2 = RandomVariate[NormalDistribution[], {1000}]; I want to ...
13
votes
2answers
379 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 ...
3
votes
0answers
197 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 ...
31
votes
1answer
570 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
246 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 ...
35
votes
2answers
675 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
122 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 ...
3
votes
1answer
498 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
217 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
140 views
0
votes
1answer
66 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
1k 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
269 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
68 views

How to generate absolute Directories in HTML

...
15
votes
4answers
1k 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 ...
2
votes
1answer
2k 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
88 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
301 views

Filling and Shading an Harmonic Curve

Suppose I have an equation plotted as shown: ...
5
votes
0answers
92 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
143 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 ...
3
votes
2answers
346 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
334 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
446 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
298 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 ...

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