5
votes
5answers
2k views

How to sum over a List

list = {11.5575, 11.397, 5.52734, 4.0878, 2.54815, 1.86652, 2.55028, 2.14952, 1.6242, 1.34117} I have a list of numbers. How do I make a function that creates a ...
14
votes
6answers
1k views

Shuffle product of two lists

I want to do the following: I have two lists {a_1,...a_n}, {b_1,...,b_n} and I would like to build now all shuffles out of this. This means all unions of these ...
2
votes
1answer
266 views

Typesetting - entering derivative in traditional form

I am trying to work out how I enter a differential in standard notation? I am familiar with using D, but everything I have tried to enter a differential has failed. ...
4
votes
0answers
233 views

Does Mathematica compute free-form-input on Wolfram servers?

I've just started to use Mathematica and I'm using the free-form input a lot. The computation time for simple problems seems to take a lot of time and my CPU isn't really used at all. I first thought ...
10
votes
2answers
632 views

Finding all possible solutions to a math mind game

In the example below the letters shall be replaced by numbers. The numbers are from 1 to 9, and each letter has the same number ...
18
votes
2answers
1k views

How can I get Mathematica to produce better Fortran code?

I am new to Mathematica and I am trying to get to it to produce some expressions in Fortran code. However, it seems that Mathematica will output duplicated expressions, that is, expressions the need ...
1
vote
2answers
929 views

Create simple table with function of column values

I just want to create a simple table: Three input columns, one output column Call the inputs {x,y,z}, each can take values ...
1
vote
1answer
251 views

Error Function Integral (Erf)

Any idea how to solve analytically this integral Integrate[(a Erf[a Sqrt[b/(a^2 + b)] c])/(a^2 + b)^(3/2), a] I tried substitution u=a^2 + b, but it didn't work. ...
-1
votes
1answer
120 views

Adding a textfield to the function that I implemented

Adding a textfield to the function that I implemented to represent the tangent or derivative of a function, but I've added so mark errors. ...
5
votes
2answers
175 views

How does the speed of WriteString compare to other languages?

I'm doing something where the most sensible approach seems to be to open a file and write to it as I process data from some large tables. Old school. While testing the program, I remembered the low ...
1
vote
1answer
285 views

Table not working with Plot

Because NIntegrate[] does not support parallel computation out of the box, I'm doing a simplified version by breaking the integration limit into pieces and using ...
7
votes
2answers
226 views

Analysis of many similar x-ray Images

From a 3d x-ray scan, I have many similar slices to analyze. Is there a way to determine the position of the three rectangles and the inner circle?
2
votes
1answer
79 views

JLink function not producing result

I have a simple JLink function as follows: ...
2
votes
1answer
161 views

project from a n-dimensional space to 2-dim

let's say that I have a sphere in $N$-dimensions $$x_1^2+x_2^2+...+x_N^2=R$$ If I want to know the projection on the $x_1-x_2$ plane in this case I can figure out myself that is a circle, but how ...
5
votes
3answers
639 views

How to define the Poisson bracket in Mathematica

If $f,g$ are functions of the independent variables $\{q_1, q_2, ..., q_N, p_1, p_2, ..., p_N\}$, then the Poisson bracket is defined as: \begin{equation*} [f, g] = \sum_{i=1}^N \left(\frac{\partial ...
0
votes
0answers
113 views

Iteration of multiple functions that feed into each other

I'm trying to figure out how to iterate through several functions that all "feed" into one-another but am having some trouble. Here are the variables: ...
4
votes
2answers
183 views

Reduce with Integer domain, but receive a rational solution

I want to find the integer values $k$ so that D[f[x], x] has integer solutions. I tried ...
1
vote
1answer
117 views

OpenSQLConnection error

I used to be able to connect to a SQL Server database. I haven't run this program for a few months. I tried it today and it failed, so I went back to try OpenSQLConnection[] and got the following ...
1
vote
1answer
81 views

Editing the Virtual Book?

It's my understanding that the Virtual Book (of mathematica 9) is in notebook (.nb) format. It appears to be a very polished style of documentation which I want to reuse (parts) of it to create my own ...
0
votes
0answers
43 views

Using an Interpolating Function as a probability density function [duplicate]

I have seen a couple of similar questions but have not been able to figure out a solution for my particular problem. I have a probability density function of two variables ...
5
votes
2answers
302 views

How to create this list more elegantly

There is list containing some $(i,j)$ values of indices. Now i want to create a matrix of dimension n $\times$ m whose entries are 1 for the indices corresponding to the given list otherwise its ...
0
votes
0answers
24 views

Create a (maybe nested) list of nminimize solutions in a loop [duplicate]

I'm a total newbie in mathematica, so need some help. I understand that my question is about basics, but i couldn't find the answer in docs, google and here. Here is what i'm trying to do. ...
2
votes
0answers
63 views

Autoupdate Section Numbers? - Technical Document Authoring with Mathematica

Technical document authoring systems are structured ways to create, manage, and update documentation for various mediums such as print, pdf, web, etc. Take a look at this technical document ported to ...
0
votes
1answer
74 views

Is there a way to redefine the looks of buttons, tabs and other UI elements?

I am looking for pointers on how to redefine UI elements (in the FE as well as in a CDF document). For example: the looks of a button, or of tab elements, and so on. (I don't mean something like ...
8
votes
3answers
1k views

Discrete Convolution

Ask to compute the convolution of 2 lists, I managed to do so, with what I feel is rather heavy : Let my 2 lists be : a = {1,2,3,4} b = {1,1,1,1,1,1}; The below function adds 0s on each part of ...
0
votes
2answers
100 views

Coloring selected elements of a list created with Table [duplicate]

I have a function that returns a list of 100+ elements, using Table[]. For simplification, let's assume that it's just ...
2
votes
2answers
97 views

How could I change the apperance of a button when some hard computation is finished?

I want to have some bottons inside manipulate to calculate some time consuming functions. For example the following code changes its color after the calculation of Total[Range[123456000]] is ...
-6
votes
1answer
379 views

How can I make a customized InputField for date inputs?

I want to make an InputField that only allows a specific date format to be entered. I want to display a field hint in the format "dd:mm:yyyy". Once the user clicks ...
1
vote
1answer
167 views
1
vote
0answers
54 views

plot cropped in large amount when setting Text Style to some specific sizes and in some locations

I make a Graphics and then add Text[Style["b",size] to it. When changing the size, I noticed that the overall graphics gets ...
1
vote
0answers
118 views

Why is my answer being displayed with “Subscript^(0,1)[a,b]”?

I type in my equations using ctrl+- to make it look nice and my answer outputs in "Subscript^(0,1)[a,b]" form? What is going on? In the answer some bits are displayed with the actual subscripts and ...
1
vote
1answer
380 views

Use Euler method to solve differential equation

Use Euler's Method or the Modified Euler's to solve the differential equation ${dy/dt=y^2+t^2-1, y(-2)=-2}$ on $[- 2, 2]$. Take h = 0.2 (...
3
votes
0answers
106 views

What is so special about variable s$?

I found a nice bug in Mathematica 9.0.1.0. Could anyone check to reproduce it? Create a file temp.txt with one line: ...
0
votes
1answer
64 views

One more question about Assumptions and Integrate

There are many questions about assumptions here. Many of them are problem specific. That is why I want to ask a question in the most general way. Why does Mathematica solves this ...
2
votes
2answers
159 views

BarChart3D does not print zeros and odd tick positions

Note: This is a version 9.0.0 problem that is fixed in 9.0.1. I want to generate a simple 3D view of some frequencies for two variables. I have the counts in a 4x3 matrix, say. This is my bar chart ...
0
votes
1answer
350 views

Remove list elements that contain NaN Symbol [duplicate]

I have a long list of lists ...similar to g = {{1,2,3},{4,2,7}, .....{1.2,9}}. Occasionally, g contains elements like ...
5
votes
2answers
593 views

Keep MathKernel Running In Background - Speed Up Execution Time

Background: I'm running Debian on a remote server with Mathematica installed. I have several dozen small mathematica files that are run in cron jobs at unpredictable intervals and updated based on a ...
6
votes
3answers
510 views

How to randomly erode a 3D distribution of points with Mma 7.0?

Suppose we have a 3D distribution of points, like the spherical ball example below : ...
-4
votes
1answer
418 views

How to generate this fractal-like 3D distribution of points in Mma 7.0?

I would like to produce some 3D distributions of points using Mathematica 7.0, that look like the picture below : How could I do that ? What are your suggestions ? What Mma 7 codes could do a ...
3
votes
0answers
109 views

Problem importing individual frames from QuickTime file

I am having difficulties with a code I am trying to run. Essentially I want to Read in a large .mov video file (60000+frames). ...
0
votes
1answer
223 views

Plotting a line segment from the degenerate case of an ellipse [duplicate]

An ellipse degenerates into a line segment when the defining constant distance from the two foci is the actual distance between the two foci. The ellipse closes into a line segment. The following ...
2
votes
1answer
124 views

Product of non-zero elements in sparse array

How can I multiply the non-zero elements of a SparseArray? Example: ...
1
vote
2answers
95 views

How can I get a fully functional FittedModel when fitting data to a pointwise function?

When I am fitting data with a pointwise function using NonlinearModelFit, the produced FittedModel fails to calculate variances ...
0
votes
1answer
116 views

Integration of DiracDelta

I just came across the following curiosity and I'm not sure whether it's a bug or just me missing something. Here's a minimal example: I defined the following "function" ...
5
votes
1answer
175 views

How to compute the residue of $e^{z-\frac{1}{z}}$ at z=0?

I've tried the following but it didn't work: Residue[Exp[z - 1/z], {z, 0}] not even this: Residue[Exp[1/z], {z, 0}] ...
0
votes
2answers
150 views

trouble with Dynamic range in SetterBar

It appears that I can set the range to a Dynamic variable in a Manipulate control, but not in a ...
1
vote
1answer
353 views

Drawing a shape on the mesh of a Plot3D [duplicate]

My question pertains to modifying the output of a typical Plot3D object, and overlaying a 2D shape, like a circle, on the 3D surface. Thinking of the surface as a stretchy surface, I want to put the ...
1
vote
1answer
101 views

How to align cells in a grid?

I would like to align the text in the gauge such as the label "AKs" is in the center of the gauge and the value (60) is in the upper right corner with a smaller font. How can I achieve this? I tried ...
0
votes
3answers
112 views

string to complex number

Consider the following list MyList= {-0.0000396, -0.0000187167, "0.10259130990561813-0.0677132394802944i"} Head /@ MyList (* -> {Real, Real, String} *) In ...
2
votes
1answer
195 views

What is an elegant way to aggregate two cash flows

When modeling a swap contract a common operation is to sum up two cash flows producing a resulting cashflow with netted amounts in the highest granularity of the two initial cash flows. What is a ...

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