3
votes
2answers
340 views

Contourplot of complex Roots

Suppose I have this equation: $$ z^2 + 3z + (x^2 + y^2) = 0 $$ I want the real and complex contour plot of $z(x,y)$. Analytically, the real/imaginary boundary is separated by condition $x^2 + y^2 ...
2
votes
0answers
111 views

Session logging of “\$Echo” and “\$Output” in Mathematica 10

I have difficulties with session logging and Mathematica 10. In previous versions, you could simply use AppendTo[$Echo, logfile] and ...
0
votes
1answer
61 views

Mapping with Trace[] [duplicate]

As part of some data anaylsis, I am using the function Trace to give me the name of an array of data, which I then use to label my plots. eg. my data array is called r1 so I run: ...
2
votes
1answer
123 views

How to solve an operator form of an integral equation by iteration method?

How I can obtain the $n^{th}$ approximation of the following Operator form integral equation? $F(t)=A(t)+\int_0^tds B(s)F(s)$, where $A(t)=\bigg{(}\begin{matrix}t&0\\Cos(t)&1 ...
15
votes
3answers
872 views

Converting hierarchies of rules to associations

The impossibility of MatchQ-ing inside and Association MatchQ-ing Associations (MMA 10) explains a problem I have. I would like ...
3
votes
1answer
75 views

Manipulate inside a function definition slows down when passed a large data set

I'm working with large data sets (>1gb) which I'm visualizing with Manipulate[]. The following example works fine for me with no additional memory overhead: ...
2
votes
1answer
283 views

GUI of a Karnaugh Map (2)

Adopting kguler's answer to my previous question, I managed to get the simplified map by using Mathematica's build-in function BooleanMinimize. The tough job left ...
0
votes
1answer
67 views

Replace all instances of Integrate by NIntegrate and add a Method option

I have an analytic expression which involves several integrals Integrate[f[x], {x, lb, ub}] where the functions f and bounds ...
11
votes
0answers
229 views

InputAliases and SelectionPlaceholder issue in V10

Bug introduced in V10.0.0 or earlier and persisting through V10.4.0 Let's create an example and do the test: ...
18
votes
1answer
211 views

Systemic bugs in GraphPlot and related functions such as TreePlot and TreeForm

Bug introduced in 7.0.1 or earlier and fixed in 10.3.0 I believe I have come across a rather curious bug in TreeForm: ...
3
votes
1answer
77 views

Finding linearly independent combination of vectors with a certain symmetry property

I have two linearly independent vectors $v_1$ and $v_2$. Is there a way for me using Mathematica to find two linear combinations $w_1$ and $w_2$ such that: $w_1$ and $w_2$ are linearly independent. ...
14
votes
2answers
452 views

Can't get Append to append a record (association) to a dataset

The Documentation Center item, Computation with Structured Datasets, implies that Append has been extended in V10 to work with datasets. But not on my computer. (I ...
2
votes
1answer
311 views

GUI of a Karnaugh Map

I intend to implement a three-variables Karnaugh map with the following code. There are two points I failed to figure out. How to remove the outer double-line border? How to change the toggling into ...
8
votes
3answers
1k views

Wrong font selection for some characters in Mathematica 10 for Linux

I've just started using Mathematica 10 on Linux and have immediately run into problems with the fonts. Fonts on Linux are always a headache, but I had managed to find a reasonable one in "Century ...
4
votes
1answer
127 views

1/0 encountered when solving an ODE

What can cause this error to show up? Clear[lambda, a, b, x, y]; ode = lambda y[x] + a b y'[x] + a (-1 + b x) y''[x] + y''''[x] == 0; DSolve[ode, y[x], x] ...
9
votes
1answer
340 views

Expanding derivatives of hypergeometric functions

Sometimes Mathematica expresses results of integration or summation in terms of symbolic derivatives of Hypergeometric2F1 function, and cannot further simplify ...
1
vote
1answer
60 views

Can someone please help me to state assumption?

I am currently trying to solve under what condition does the following term will be zero? ...
11
votes
4answers
296 views

Recognizing special cases of a defined function for permuted arguments

I have a number of ugly ways to implement the following pattern recognition task, but I'm looking for something elegant to keep my notebook tidy. I need to define a function of six variables ...
7
votes
4answers
422 views

Conditional Expectation — How can Mathematica find a more general closed form?

Mathematica can't find a solution to this Expectation. ...
2
votes
1answer
124 views

Finding a root of a parameterized integral

I have a function given as a parameterized definite integral: f[a_] := Integrate[BesselJ[0, x - a] BesselJ[0, x + a], {x, -∞, ∞}] I suspect it has a root near ...
3
votes
4answers
268 views

EventHandler Not Detecting KeyDown

I am trying to use EventHandler to detect KeyDown within a LocatorPane. Anytime I press a key inside the LocatorPane the proper action is not executed (doesn't matter which key I choose) but rather ...
4
votes
2answers
557 views

Conversion of 3D plot to 2D Contour Plot

Is it possible for Mathematica to convert a 3D plot into a 2D contour plot without having to recompute the values for each point? I realize that looking directly down at the 3D plot will be similar to ...
1
vote
2answers
71 views

How does one go from a string to the contents of a variable with the same name?

What command should I use if I want to convert a string to the contents of a variable with the same name as the contents of that string withing a function. ToExpression[] doesn't seem to do it. ...
22
votes
7answers
2k views

Is there a way to recreate the typical Red/Blue-Postereffect using Mathematica?

I think nearly all of us have at least once seen an image like this: So I wondered whether it is possible to recreate this effect using Mathematica because it seems like it wouldn't need that many ...
0
votes
0answers
33 views

Expressions to functions, and evaluation [duplicate]

When calculating derivatives a expression is the result: in:= f[x_,y_]:= 1 + 2 x + 3 x^2 y + 4 x y^2 in:= D[f[x,y],x] out= 2 + 6 x y + 4 y^2 how do i make this ...
8
votes
1answer
565 views

How to generate nonperiodic tilings?

I need to generate nonperiodic tilings which are similar to the attached figure (kite-domino tiling). I was thinking the code is similar to the code for the Penrose tiling. However, that code is too ...
0
votes
0answers
114 views

Problems with NMinimize

I have written some functions that take a matrix and find its minimum inner product with a specific set of vectors ...
0
votes
2answers
149 views

Plot a perfect looking circle using two functions, always look like an ellipse [duplicate]

I want to use the the following two functions to plot a perfect looking circle, but the graph always ends up looking a bit squashed. I've been playing with some of the parameters of the function but ...
2
votes
3answers
1k views

How to use this Lorentzian function fit my data, I tried NonlinearModelFit, it always resulted with an error

The data is uploaded to Ideone http://ideone.com/ktIbVk , my code is : ...
0
votes
1answer
89 views

What is wrong with ContourPlot [duplicate]

Why does this plot have a big blank hole in it? ...
8
votes
7answers
1k views

Populate an upper triangular matrix from a vector of elements

What is the best way to populate an upper triangular (or alternatively: lower triangular or symmetric) matrix from a vector of elements? This example input: ...
3
votes
1answer
212 views

Aborts and beeps without error warning

I have a piece of code that generates a figure, performing a calculation to generate each pixel. At a certain resolution it runs fine, but after a high enough resolution it fails. Mathematica beeps ...
3
votes
2answers
195 views

Retrieving other information on CountryData

The following input will produce some answers, however how do we find out other details, such as the specific year the result corresponds to, as well as the source from which the data is obtained? ...
5
votes
2answers
336 views

Table with multiple iterators running parallel

I want to use Table to generate a list, but it only allows one iterator to increment at a time. So in ...
0
votes
2answers
56 views

Multiply value if it includes a period

I download data from an online source, now I have a problem: the source code doesn't allow to differ between values of 10 (which actually stands for 10) and 10.000 (which is 10'000, but Mathematica ...
5
votes
1answer
484 views
3
votes
3answers
210 views

Multivariate Polynomial Manipulation

I have a large homogenous multivariate polynomial in, say, 5 variables $a,b,c,d,e$. As an example take the polynomial $$a^4+2abcd+a^2 b^2+e^4+cde^2.$$ Now I would like to replace $k$-th power of any ...
3
votes
0answers
71 views

Error solving third order ODE in version 10. No error in V9. DSolve`DSolveKovacicDump`

This is an ode which is solved with no error in V9, but gives a very strange error in V10. Is this a regression bug? On version 9, the ode is solved with no error ...
3
votes
5answers
259 views

Take the next element in a nested list

My problem is the following: Consider a list of elements. To better understanding my following explanations, I would take this example: ...
3
votes
1answer
272 views

Use of Ito's lemma in ItoProcess

In the documentation for the ItoProcess it says: Converting an ItoProcess to standard form automatically makes use of ...
11
votes
2answers
428 views

Connect Frontend to Kernel Started by JVM via JLink

I have a MathKernel started and controlled via JLink from a JVM. The $CommandLine for this kernel is: ...
12
votes
2answers
277 views

Evaluate selection in new window or new notebook?

Sometimes when you have long code you need to check some part of this code. the way I am using currently is to selected the part that I want and then copy it to new notebook and then evaluate it ...
4
votes
4answers
362 views

Automatically growing lists as in MATLAB?

Is there a way to add elements to a list at positions outside the current list's length? Something equivalent to the following MATLAB code snippet: ...
7
votes
1answer
333 views

Porting code from MATLAB

I'd like to switch from MATLAB to Mathematica for my research in digital signal processing. I used Mathematica a lot during the '90s but I haven't used it since then, so I might as well be a complete ...
4
votes
3answers
521 views

How to solve an integral equation by iteration method? [duplicate]

How I can obtain $n^{th}$ approximation of the following equation $f(t)=t+\int_0^tds f(s)$ by iteration method?
4
votes
1answer
220 views

How to input and output partitioned matrices that show partitions and compute as normal?

I want to demonstrate multiplication of partitioned matrices as in the example here. Using the Insert Menu, you can build a matrix and draw lines between rows and columns. However, I want to be able ...
1
vote
0answers
204 views

Solving PDEs with complicated boundary conditions

The system I'm trying to solve is $$\nabla^2 C_{(r,\theta)} =0$$ $$C_{(\infty,\theta)}=C_0$$ $$ [ \frac{\partial C_{(r,\theta)}}{\partial r} \cos(\theta)+\frac{1}{r}\frac{\partial ...
0
votes
3answers
182 views

List of Coefficients of Expression with symbolic Terms

(I am affraid that this is a duplicate, but I read several already asked questions and non of them helped me. If it's already answered, please tell me) I have expressions like this ...
2
votes
0answers
159 views

Mathlink program with low cpu usage on linux machines only

Question I am incorporating some c++ code via Mathlink into my simulations in Mathematica. My questions involves the execution efficiency of the c++ code on different machines. For example, on my ...
2
votes
1answer
92 views

ZTest result not making sense

I'm using version 10. I'm having difficulty with understanding why I'm getting some output from the ZTest function. Here is the code for my specific example. ...

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