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4
votes
2answers
172 views

Pattern match any member of a Context

Let's say I have four functions: x, y, X`x, and X`y. ...
20
votes
1answer
3k views

How to extract metadata from an image of a business card?

I'm trying to digitize some documents, and I came across a very cool app called camscanner app which performs parallax transform and ocr very nicely, now I'm implementing it in mathematica... Given a ...
7
votes
2answers
492 views

What are Controlling and Computing Processes?

My wolfram user portal claims that I have 2 controlling processes and 8 computing processes. Mousing over the question mark gives me some information, but I still don't fully understand what this ...
2
votes
2answers
278 views

Problem with high parameter values in ParametricPlot

I tried to plot the following function as a Parametric Plot. When I include values for w up to 1 the plot looks fine, but I need this plot for values up to 100 or 1000. ...
1
vote
1answer
1k views

Boundary Value Problem

I have to solve this boundary value problem: $$\frac{\mathrm{d}e_{3x}}{\mathrm{d}l}=(M_0+F_{0z}x-F_{0x}z)e_{3z}$$ $$\frac{\mathrm{d}e_{3z}}{\mathrm{d}l}=-(M_0+F_{0z}x-F_{0x}z)e_{3x}$$ $$\frac{\mathrm{...
1
vote
1answer
188 views

Seemingly simple optimization problem is slow

I'm trying to generate a demand curve numerically, given a utility function. The function for the demand is defined like so: ...
5
votes
1answer
268 views

A triple sum related question

I'm trying to compute the triple sum Sum[ 1/(i! j! k! ), {i, 1, Infinity}, {j, i + 1, Infinity}, {k, j + 1, Infinity}] but Mathematica doesn't return any value. ...
3
votes
1answer
997 views

Nested Sums to multiple sum

I would like to automatically "move nested sums to the left". I mean, just take out of an expression all the summations and go from a nested Sum to a multiple sum. Something like starting with: ...
4
votes
2answers
2k views

How can I transform a list of binary digits into integers?

I want to transform a list of binary digits into integers. With the Table function, I produce four lists of binary digits of length 32. Then I tried to turn these ...
2
votes
1answer
1k views

define the range of Longitude from 0-360 in the World plot from CountryData

How can I change the Longitude range to 0-360 in the such plots? ...
5
votes
1answer
497 views

Using Hold correctly with Simplify and ComplexityFunction

It seems like Mathematica immediately evaluates the expression Sqrt@I to (-1)^(1/4). I'm trying to use ...
0
votes
1answer
87 views

How can I seperate specific elements from the list? [duplicate]

Possible Duplicate: Question about MapThread and Dynamic I write a function name as inputFieldsList and it returns both ...
1
vote
1answer
143 views

How can I make my code simpler?

I want to find similar letters ...
15
votes
3answers
2k views

How to remove constant background from an image?

I'm not sure how to remove the paper background from this logo with v9. This is really not the same as this question, but I think similar methods apply.
8
votes
1answer
254 views

How to make MousePosition more reliable

This takes a little patience to reproduce, but I got a screenshot of it in version 9 on Mac OS X 10.7.5: With a small Graphics object, it occasionally happens that ...
1
vote
1answer
3k 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, -...
0
votes
0answers
100 views

Plot using Manipulate or Animate [duplicate]

Possible Duplicate: PolarPlot render oddities When I use manipulate or animate function, the result shows a non-smooth plot. How to make the manipulate or animate commands show good and smooth ...
4
votes
0answers
253 views

Possible to batch WolframAlpha queries?

Sometimes I want some country data not available from CountryData. And issuing things like: ...
11
votes
2answers
332 views

Plotting a function, x = 1024

The function s12 = 1/(Log[2^x]*((7.537/(x^2)) + (30.148/((2 + x)^3)))) returns expected function values for ...
3
votes
1answer
282 views

Problem with dynamic MouseAppearance updating while “MouseDown”

my problem is with combining EventHandler and MouseAppearance. I want to change cursor appearance if I have primary button ...
1
vote
1answer
554 views

Solving the wave PDE using the Fourier method

I am trying to solve the wave PDE using the Fourier method and I need to animate the plots of the partial sum of order 45 -- U45(x,t) with initial conditions U45(x,t0), {t0, 0, 12, .2}. I am ...
4
votes
2answers
174 views

LayeredGraphPlot: two instances of the same label

What I'd like to do is to have the same label more than once in the plot. I.e. I do not want the edges to direct toward the first instance of that label! For example: ...
9
votes
3answers
412 views

Find all the last weekends in a year

In order to obtain the weekends of a year you'd use something like this: ...
7
votes
2answers
1k views

DatabaseLink`: MySQL query with client/server compression

I'm trying to reduce transfer time when accessing rows of a mysql table over a network, where each row has a lot of data. Is there a way to enable client-server compression when accessing a mysql ...
1
vote
0answers
55 views

Interested in knowing what substitutions were made to perform an Integrate[]? [duplicate]

Possible Duplicate: How does Mathematica integrate? Mathematica can perform the following integral with apparent ease (returning very fast with the result) ...
38
votes
9answers
5k views

Removing elements from a list which appear in another list

There are two lists {a, b, c, a, d, a, e} and {a, c, a}. I need to remove those elements from the first list which appears in a second list, to get {b, d, a, e}
3
votes
3answers
172 views

How to identify patterns in a tensor-polynomial and replace appropriate symbol?

I want to write a function tensorReplace[input] that takes a tensor polynomial in $r_i$ such as $r_i r_j r_k+r_i q_j q_k +q_i q_j q_k$ , and replaces each monomial ...
17
votes
1answer
441 views

Adding three integer sparse matrices is very slow. Adding only two is fast

Bug introduced in 9.0.0 and fixed in 10.0.0 Adding more than two sparse matrices in one step in Mathematica 9 is very slow (in fact I couldn't even wait for it to finish). Here's an example. Let's ...
7
votes
5answers
3k views

sliding a tangent line along a curve

I am confused by Dynamic. I am trying to slide a tangent line along a curve, without using DynamicModule, so that I can include ...
2
votes
0answers
191 views

Taking Log Transformation of unit circle using Presentations package

...
5
votes
3answers
9k views

How can I solve this PDE with initial conditions?

I wish to solve the following second order partial differential equation $$u_{tt}=c^2 u_{xx}$$ with the initial conditions $$u(x,0)=e^x,\quad u_t(x,0)=\sin x$$ In Mathematica, I evaluated the ...
13
votes
2answers
17k views

Plotting the frequency spectrum of a data series using Fourier

testData = Table[N@Sin[500 x], {x, 0, 100}]; ListLinePlot[Abs[Fourier[testData]], PlotRange -> Full] Gives me Which I do not expect because the Fourier ...
14
votes
2answers
817 views

How to interpret the FullForm of a SparseArray?

SparseArrays are atomic objects, but they do have a FullForm which reveals information about them. What is the meaning of the ...
25
votes
4answers
1k views

Efficient circular buffer?

I wish to create an efficient circular buffer. That is, I wish to keep a fixed length list while appending a new value and dropping the oldest, repeatedly. As we know lists in Mathematica are ...
4
votes
1answer
252 views

In a DynamicModule, is it possible to use multiple EventHandler declarations? [duplicate]

Possible Duplicate: Wrapping EventHandler by Table I am running Mathematica 7. However, I am new to using Dynamic, ...
3
votes
3answers
206 views

How can I efficiently enter multiple instances of data?

I would like to plot the normal distribution for a population of human heights. My question is how can I input multiple frequencies for the same variable, without writing them out one by one. e.g. I ...
2
votes
1answer
149 views

Error in setting matrix elements [duplicate]

Possible Duplicate: How to Set parts of indexed lists? For better organization of my code, sometime I use data objects in the form: ...
5
votes
2answers
5k views

How do I export matrices into matlab format?

For example: ...
6
votes
2answers
303 views

Why rule does not work if Flat attribute?

The following works: ...
0
votes
1answer
214 views

Apply rule only if applicable? Check rule applicability? Custom unapplicable rule?

How to avoid recursion in the following example? ...
1
vote
1answer
448 views

Why does the mean in my coin tossing simulation not approach 1/2?

I simulate a simple experiment, a coin flip. What I do is accumulate the mean of the results up to the i-th experiment. What I can't figure out is why the computed means do not asymptotically approach ...
5
votes
1answer
388 views

Convert boolean test function to pattern?

What is a "reverse" to MatchQ? MatchQ converts pattern into boolean function. So how to convert back? Suppose I want to use ...
10
votes
1answer
498 views

Custom attributes?

Is it possible to assign custom attributes to symbols and check them later? SetAttributes[a, b] says ...
1
vote
1answer
576 views

Complex Region using Presentations Package

Just purchased the Presentations package. First sketched this region: ...
4
votes
2answers
259 views

FindShortestPath with negative weights isn't working

I have the following functions defined: ...
7
votes
1answer
253 views

Restrict access to Lightweight Grid

When using the default configuration of the Lightweight Grid Manager, anyone connected to the same internal network where the grid severs are can launch kernels on the grid. What possibilities are ...
2
votes
1answer
977 views

How can I solve an exponential inequality in Mathematica?

I would like to solve the equation: A Exp[m t + s Sqrt[t] x - 1/2 s^2 t] >= K with respect to x (which is in the exponent) ...
4
votes
2answers
376 views

Programmatically writing to a notebook in TraditionalForm

I'm trying to get a Cell to appear in TraditionalForm when using NotebookWrite. Here is the closest I can get: ...
23
votes
5answers
2k views

How to get the real PlotRange using AbsoluteOptions?

Bug persisting through version 12.0.0.0 The problem in general involves the unreliable behaviour of AbsoluteOptions when option values are implicitly specified (e....
5
votes
1answer
1k views

Is the source code available for examples in the “Mathematica Cookbook” by Sal Mangano?

I looked around a bit and didn't seem to find it. Not as obvious as Wrox books make it, for example. I came across a pdf of the book online [I paid for the paperback] but pasting the code from the ...

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