3
votes
1answer
68 views

Restricting a plotted expression to reals in a Manipuate

I have an expression from which I'm trying to create a plot that I can manipulate. The expression contains Abs, and I only want to have it evaluated for reals. What ...
1
vote
2answers
1k views

Discrete FFT of non-periodic signal excited by short pulse

Say I have a signal F(t) which represents a excitation by a pulse (so it is not periodic and declining to zero amplitude). According to this answer, for instance, ...
1
vote
2answers
498 views

Implicit differentiation to find the slope of the tangent line to the graph at the indicated point [duplicate]

I used ContourPlot to plot the graph of x Sin[Pi y] - y Cos[Pi x] == 1 with the following input: ...
2
votes
5answers
368 views

Creating ordered triplets from an Excel sheet

I have an Excel sheet of the form: " " a b c 1 R S T 2 U V W 3 X Y Z Where every entry is a number (except the blank quotes, ...
2
votes
1answer
253 views

Export to mat file does not work

I use this command from the Mathematica documentation center Export["1.mat", {"t" -> {{1,2,3}},"u" -> {{4,5,6}}}, "LabeledData"] to save data as mat file ...
1
vote
1answer
99 views

NMaxmize with a list of variables

I want to use NMaximize to find the maximum value of a function with multiple variables. The problem is I would like to set this up so the number of variables is only decided when the function sees ...
0
votes
0answers
55 views

DeleteCases and Inequalities [duplicate]

I would like to remove cases from a list according to an inequality rule - e.g. remove all values less than x. I can do the following but this seems very clumsy: ...
7
votes
1answer
178 views

Crash with subsetting TemporalData

The first line gets a single sample path for an M/M/1 queue for time between 0 and 100. No problem, I can plot it, etc. ...
16
votes
1answer
299 views

Why is ReplaceAll behaving like this?

I'm learning to use the ReplaceAll function and I found the behavior of which is quite confusing. For Sqrt[f[x, y]] /. f[___] -> u Mathematica returns ...
1
vote
2answers
592 views

Dropping Higher Order Terms in symbolic evaluation

I have a series of symbolic manipulations (along with some coefficients). As a sample, here is one of the intermediate forms ...
11
votes
1answer
349 views

Using non-trivial objects in RLink

I would like to use RLink to access igraph, which has an R interface. I do not know R; my motivation for learning it is to be able to access igraph easily. I installed igraph using ...
0
votes
1answer
105 views

Should Read[] not close its Stream? [closed]

I read a record from a file. Read[file,Record]; It reads and opens a stream. Should Read not close its stream after ...
1
vote
1answer
187 views

Match and replace subexpression

I would like to replace the expresion $(n1-1)$ to $z1$ in following: In[1] := 2*n1*p[n1-1,n2] Out[1] := 2*(z1+1)*p[z1,n2] I have tried ...
2
votes
2answers
373 views

How to prevent errors in Manipulate with ListPlot when a result is an empty list?

I am trying to plot two lists, where one is the reference list, and the other is only used to select and highlight the first list. Basically, I want to use the selection list ...
2
votes
1answer
270 views

Is there any way to force Mathematica to collect a symbol in a polynomial?

Let's say that I have a polynomial like this: a + b + c Is there any way that I can get Mathematica to transform it to: ...
3
votes
1answer
352 views

How can I connect database(MSSQL Server) with Mathematica?

Newly I started working with database(MSSQL Server 2012). by google help, I created Table name as EmployeesList and also ...
0
votes
1answer
824 views

How can I find the Fourier series from discrete data?

I would like to define the function with Fourier series when I just have discrette data. (I don't have a specific function). I can draw the graph using the data, but I don't have a idea how can I get ...
6
votes
2answers
253 views

Unexpected behavior of rule matching a pattern

I am a beginner exploring the world of Mathematica. I expected the following code T[6, 5, 4, 1, 2, 3] /. {T[a___, 1, b___] -> Length[List[b]]} should return ...
0
votes
2answers
101 views

Getting value of clock [duplicate]

I have the following code: a = Dynamic[Floor[Clock[2]]] (*So this basically alternates between 0 and 1*) If[a==1, Print["true"]] But this doesn't work, it ...
3
votes
3answers
140 views

How to create a button that colors a selected piece of text in a cell?

I use Mathematica 9.0.1 and I want change the color of a selection in a text cell using a button. But when I use this code it changes the color of the entire cell. ...
4
votes
2answers
241 views

Background color of Code cell lost when convert a notebook file to pdf

Well, I have a notebook with the built-in stylesheet Preprint, which I'd like to convert it to pdf. Everything works well except for the code cells(I use the shortcut key alt+8 to create cells of code ...
4
votes
6answers
2k views

Removing zero values from ordered pairs

I have some processed data, which are basically a collection of ordered pairs in the form: {{x1, y1}, {x2, y2}, ..., {xn, yn}} Ordered pairs which have either a ...
1
vote
3answers
149 views

problem with Importing multiple files

I need to import about 100000 "dat" files to my progrom. I want to do this using the last answer to this question: Importing multiple files using a for-loop I know that I should define a list of all ...
-1
votes
1answer
341 views

Integral evaluation taking too long [closed]

When I try to evaluate the following integral, it runs for a much longer time than I think is should without producing a result. What might be the problem? Can anybody please point it out? ...
-1
votes
1answer
575 views

How can I draw a Cuboid given its center and its dimensions? [duplicate]

I want to draw a Cuboid accroding to the coordinates of its geometric center and its dimensions, rather than its diagnoal coordiantes. And How can I draw a triangular prism?
9
votes
1answer
303 views

Efficiently filling area with disks located at certain points

Starting from a set of points, I want to fill an area using disks. Each disk's center should be one of the points and the disks should not overlap. I've managed to write a function that, given a list ...
3
votes
2answers
239 views

How to migrate or export projects with Workbench

Imagine the following scenario: user A is developing a project with documentation in workbench. She wants to give her (unfinished) work to user B , so that user B can continue work on the project and ...
0
votes
2answers
255 views

Reduce on equations involving integrals

Here's part of problem from a college physics text: A time-dependent force F = (8.00 i - 4.00 t j) N (where t is in seconds) is applied to a 2.00-kg object initially at rest. (a) At what time ...
4
votes
3answers
546 views

Defining a new Function using RegionPlot

I'm trying to make images like this: to illustrate 2D integrals to a calculus class. I used the code ...
2
votes
2answers
847 views

Using ChemicalData to make molecule graphics

I would like to take the acetone $((CH_3)_2CO)$ and chloroform $(HCl_3)$ molecules that Mathematica's chemical data provides, and plot them together. I want to show how chloroform can hydrogen bond ...
0
votes
2answers
1k views

Sequence of data in 3D, joining the points

Let me just first say I am not actually trying to find a function for these set of data. All I am doing is joining the points to make a line. Basically let's say I have some data, which I cleverly ...
0
votes
0answers
37 views

Symbolic Calculations with formal matrices [duplicate]

I want to make calculations with matrices in the form (for lovers of statistical mechanics, is just the first step replica symmetry breaking) ...
1
vote
0answers
172 views

Manipulate - Flickering graphics

I am new to mathematica and was experimenting with NDSolve and doing a simple demonstration of orbital motion and Newtons laws. I put together the following code which all seems to work except the ...
0
votes
2answers
169 views

Iterating Reads From a Text File and Writing the Results of Operation

I have a very large text (TSV) file. I am able to now read single line, thanks to StackExchange. I am able to read a part of that line using the part operator. I want to iterate through the whole ...
3
votes
2answers
718 views

NDSolve: Normalizing at every step

Suppose I have an transport equation with an initial conditions: ...
5
votes
1answer
136 views

Functions, Options and Symbols

In the normal Mathematica language, where no built-in symbols are redefined and no evil things happen, is it a valid assumptions, that no function symbol (Plot, ...
11
votes
3answers
408 views

Replace operators

/. can be used to replace variables but how can one replace operators. For example in a * b, ...
8
votes
1answer
395 views

Looking for a package regarding Schur Polynomials and Kostka numbers

I'm currently looking for any Mathematica package that involves Schur polynomials and/or Kostka numbers. More generally, I'd be happy with anything that expands on symmetric polynomials in general. ...
0
votes
0answers
28 views

What is the precision of this number? [duplicate]

In a matrix evaluation, I got the following number. 2.8330574963868513` I understand that the number after ` shows the precision of the output number. But this ...
3
votes
2answers
469 views

BC for transport equation using NDSolve

First I can solve a transport equation with a source (Is it still called transport equation?) using DSolve. The form of the source serves only as an example. It can ...
4
votes
1answer
173 views

Automatically tracing and keeping ViewPoints in a list while manually rotating 3D graphics

I will need to make a video from the manual rotation of a 3D graphics. In order to do this, I will need to record the set of all view points that I made during rotation. There is method that we can ...
6
votes
4answers
1k views

Left-aligned PlotLabel?

Is it possible to have the text generated by PlotLabel (or any other function) aligned to the left side of the plot instead of in the center?
4
votes
0answers
518 views

Kalman filter by hand

I am now learning the Kalman filter and wants to implement it by hand to understand it better. To be specific I want to first simulate a sequence of data by $$ \dot x=Ax+Bw\\ y=Cx+Dv,\\ ...
15
votes
6answers
703 views

Matrix Rotation

If I have a matrix of any size, say $\begin{pmatrix} 72 & 32 & 64 \\ 18 & 8 & 16 \\ 63 & 28 & 56 \\ \end{pmatrix}$ $\begin{pmatrix} 72 & 32 \\ 18 & 8 \\ 63 ...
2
votes
0answers
380 views

differential equations with implicit functions

I have an ordinary differential equation that contains coefficient functions that depend implicitly on the independent variable via an algebraic equation. I am trying to go ahead and use NSolve to ...
2
votes
0answers
238 views

Negative power instead of fraction

Solve returns a solution in the form {{x->y/a^2 + y^2/a^7}}. Since I want to process the input (with another program) in terms of Laurent polynomials, I would ...
1
vote
1answer
107 views

Factorize and find the null space of a polynomial in several variables [duplicate]

I've been asked to factor the following polynomial: poly = 6 x^3 + x^2 y - 11 xy^2 - 6 y^3 - 5 x^2 z + 11 xyz + 11 y^2 z - 2 xz^2 - 6 yz^2 + z^3 And to solve for z so that poly = 0 Can anyone help ...
0
votes
0answers
262 views

FindMaxValue vs FindMaximum

I'm studyng the maximum value of the following function ...
-3
votes
1answer
167 views

Limit of a subsequence

I am trying to calculate limit for a subsequence <${ a }_{ {n }^{ 2} }$> because I was trying to see that limits of sequences and subsequences are both same. I was able to generate the sum for ...
4
votes
2answers
2k views

Defining a non-commutative operator algebra in Mathematica

I am trying to develop a function(s) to do some commutator algebra to compute the enveloping algebra and ideals of a Lie algebra. For example if I have $SU(2)$ algebra generated by $L_i$ ($i=1,2,3$), ...

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