-1
votes
1answer
37 views

How to loop in reverse order?(e.g. for i from 10 to 1) [on hold]

I have a list F = {382.856, 638.53, 915.482, 1192.44, 1469.39, 1746.34, 2023.29, 2181.91} And I want to use it to calculate V: I think it should be something ...
3
votes
1answer
81 views

Butterworthfilter data filter

I am currently doing a signal analysis and filtering using Matlab. The filter I am using is Butterworthfilter model to filter scattered data (vector data). I am using Matlab as follows: ...
1
vote
2answers
102 views

How to create a list with subscript?

I have to calculate: How can I create such a collection? Do I have to set it manually(one by one) like G1=1, H1=1, G2=2,H2=.....? UPDATE: Addtional Questions: How can I store te results into ...
4
votes
1answer
202 views

Structure of curated data?

Is there a way to programmatically access the structure of curated data present in Mathematica (for each type of information, for example for CountryData or ChemicalData) that would allow access to ...
0
votes
0answers
58 views

speeding up a function

I need to marginalize a distribution. I was suggested to use the code in this thread. This works just fine, but the problem is that the construction of tab (please ...
27
votes
5answers
1k views

Identifying critical points of 2/3D image/cubes

Upshot I am interested in identifying critical points of a 3D field/cubes (maxima, minima, tube-like and wall-like saddle points) and 2D field/image (maxima, minima, saddle points). I.e. the ...
12
votes
4answers
848 views

how to differentiate formally?

I have been wrapping my head around this for a while now and I have not found a solution so far. I want to work with an arbitrary number of variables in mathematica and use some built in functions. ...
3
votes
2answers
105 views

Controlling spacing of histograms in Histogram3D

I have five histograms, hist1 = Histogram[data1, 20], to which I append {1, 2, 3, 4, 5} via ...
0
votes
0answers
53 views

About how Mathematica understands the branchcuts of the complex logarithm [Part 3]

One understands that for the function $\log(z^2+a^2)$ Mathematica implicitly puts the branch cuts to be starting at $\pm ia$ and going up/down respectively on the imaginary axis. The phase of this ...
0
votes
0answers
76 views

Mathematica examples with many calculations? [on hold]

This what I'm trying to do with mathematica: I have to do a lot calculation, and use results from previous calculations to conduct followings. But I only know to use Mathematcia in this way: The ...
9
votes
2answers
227 views

Select cases from a list

I have a list in the form : {1,1,1,0,-1,-1,1,1,1,0,0,0,0,-1,-1} No I'm trying to select only those sequences which start with 1 have a zero (or many zeros) ...
1
vote
2answers
365 views

Faster way to test if an expression equals zero

I want to test if expressions (mix of variables, functions and numbers) are zero valued, as fast as possible, and PossibleZeroQ is sometimes very slow. One solution ...
1
vote
0answers
23 views

Correct use of Mathlink's MLGetRealList

I am attempting to use Mathlink from C. I have managed to return single values from mathlink to my c program, but I am having trouble with lists. Consider the Mathematica operation: ...
1
vote
0answers
65 views

FindRoot in range

I am trying to find all roots in a range, using y /. FindRoot[Sin[y] == 0, {y, #}] & /@ Range[7] which gives ...
0
votes
1answer
90 views

How to solve this integral equation?

I am trying to solve for x the integral equation : ...
0
votes
0answers
36 views

TableDirection in TableForm

I got confused about what does "the outermost dimension" and "the first dimension" mean in the document I snipped. Does it mean row or column?
0
votes
2answers
55 views

Manipulate executes twice [on hold]

I need help, guys! Here the script: ...
0
votes
0answers
85 views

Issue with Set function

Tables often come with column headers. Indexing the columns with the header is a natural thing to do. Although a proper dictionary is the usual solution in such a case, I find it often practical and ...
0
votes
0answers
74 views

Manipulate for Electric Field

I'm kind of new to Mathematica but I'm getting the hang of it slowly. Anyways, I'm trying to do a project on the electric field of two particles so my professor helped me with this code (sorry in ...
2
votes
1answer
39 views

How to distribute PermutationProduct over the sum

Assuming I have two elements of the permutation group algebra $a_1$, $a_2$ such that $a_i=\sum_{p\in S_n}\alpha_pp$, I want to define a linear product $\odot$ that distributes over the sum and pulls ...
0
votes
0answers
70 views

an NIntegrate inside a manipulate in mathematica was working and suddenly won't work now. it says indeterminent and it doesn't make any sense why

my title says pretty much everything heres what I'm entering. NumericQ returns a false value but it was true before. Im loosing my patience because this is so ...
0
votes
1answer
66 views

Matrix Operation

I have a $3\times3$ matrix A, and a function sTrans that outputs two $3\times3$ matrices in a list when given a $3\times3$ ...
0
votes
0answers
31 views

“NotebookPredictions” [on hold]

I have deleted Mathematica user folder, as well as reinstalled Mathematica, but I keep getting error message: The front end encountered an error while processing a "NotebookPredictions" packet. What ...
2
votes
2answers
179 views

How to select the first “lowest” (first valley) number in a list?

I would to select the first valley of the list of coordinates below. It should be {3, 1}. ...
2
votes
1answer
60 views

Generating the set of all strings within a fixed edit distance of a initial string?

Provided a starting string initialString, and a particular alphabet of allowed characters {"A","B","C","D","E",...}, how can I ...
0
votes
1answer
88 views

Getting cdf content from nice Wolfram info graphic

There is a very nice cdf info graphic on the Wolfram Webpage (http://www.wolfram.com/cdf/uses-examples/infographics-full-example.html). I'd like to have a look at the code as I'd like to do something ...
3
votes
2answers
91 views

How do we make a negative integer out of a string of a negative number and vice-versa?

Negative numbers are not taken into consideration by mathematica's built-in functions. FromDigits["-2"] Gives me this message: ...
1
vote
2answers
121 views

X-Y scatterplot

Hi I have a simple question. How do I plot the following with Day 1 as my X axis and Day 2 as my Y axis? I need the 22 variances plotted according to the Day they were taken from (these were ...
-2
votes
0answers
59 views

Shooting method [on hold]

can someone look at my equations http://imagebin.org/306581 , and tell me how would I simulate it? Any idea would work. I am looking for a start. I have a code in matlab, but its taking vary long, and ...
7
votes
1answer
76 views

Explain the difference between ViewPoint and ViewVector?

I've read the documentation, but am still very unclear as to what the difference is between ViewVector and ViewPoint for ...
2
votes
0answers
59 views

Understanding of method for NDSolve

I used automatic method for NDSolve. Then I asked myself - which method Mathemathica prefered? I got an answer for this question on this forum, that I need to use: ...
1
vote
0answers
34 views

Conjugate of InterpolatingFunction?

From NDSolve, I got this: {{a1 -> InterpolatingFunction[{{0., 40.}}, "<>"]}} What would be a sensible approach to ...
3
votes
2answers
70 views

Finding all instances of length $N$ common subwords in two strings

Given a pair of strings, I'd like to return a list of all common subwords of a fixed length of "n" characters (i.e. contiguous subwords of length "n" that occur in both strings), allowing for ...
10
votes
4answers
227 views

Efficient way of identifying the indices of first occurrences

It seems to me like identifying the first occurrence of unique elements should take about the same amount of time as it takes to delete duplicates. My data sets are much larger than this (...
0
votes
0answers
32 views

Find the values of parameters so that the matrix is symmetric positive definite

Good evening , I have a matrix 20x20 in symbolic form. The matrix depends on 5 parameters (a,b,c,d,e). I would like to get the interval of each parameters that ensures that the matrix S is symmetric ...
0
votes
0answers
31 views

Meaning of FourierParameters [on hold]

Many of the Fourier analysis functions take a FourierParameters option. FourierParameters. The documentation just says is an option to Fourier and related ...
7
votes
2answers
210 views

Scan vs Map vs Apply

I cannot understand the difference between Apply, Scan, and Map. I have tried to play with ...
4
votes
2answers
145 views

How can I avoid getting the error message Goto::nolabel in my code?

If anyone could suggest a reason why Label[begin] ... Goto[begin] would return Hold[Goto[Begin]], and (better) how can I avoid ...
0
votes
1answer
43 views

Questions regarding DictionaryLookup of Mathematica

a. Make a function longest[lang_] that gives the length of the longest word in the dictionary of lang. You should get ...
0
votes
1answer
46 views

Loading Statistics`Library`

I need to use a number of functions from theStatistics`Library` namespace. Since that is a bit of a mouthful I would like to import it, but I get errors: ...
1
vote
1answer
82 views

Overlay Rectangle on a ListPlot

I have a ListPlot of 100 data points in the range of 0 and 1. Now I'm trying to find a way to overlay (four) rectangles onto the listplot in 0.25 steps horizontally. Essentially I just have BinLists ...
0
votes
1answer
330 views
2
votes
1answer
68 views

Importing data from excel and assigning a variable to each of its columns

How should I assign variables to the data imported from excel containing 3 columns which are time, mean and standard deviation. I want to perform operations on the three variables to get new ...
1
vote
2answers
62 views

How to sort the adjecency matrix of bipartite graph so to have two off-diagonal blocks

In a bipartite graphs there are two class of nodes, say A and B. Each node of class A may interact only with nodes of the class B, and viceversa. The corresponding adjecency matrix is thus composed by ...
0
votes
0answers
39 views

Ticks don't display on Y-Axis of Histogram when using PlotRange

I have a histogram, if I create it without specifying the PlotRange it works fine and the ticks on the Y-Axis are displayed ...
1
vote
0answers
48 views

Solving for a charge distribution from a dipole moment [on hold]

I've been looking around but I haven't been able to find any way of solving this conceptually simple problem. In short I am trying to find the charge density in a dielectric in an external electric ...
0
votes
1answer
107 views

Exporting tables of interpolating functions

A few weeks ago I asked a question about manipulating parameters in NDSolve (Looping with NDSolve?) , and received some very helpful advice about the manipulate environment; now I want to take the ...
0
votes
2answers
34 views

Expand expression into quotient of negative power series

I have a function T(z) and want to expand it to the following form: At the end I want to have a list of equations, which can calculate a0, a1, a2, b0, b1 and b2 with different values of h1, h2, ...
0
votes
2answers
26 views

How can I troubleshoot a PDF that fails to import?

I'm trying to import a PDF file whose text I'd like to parse, but I'm getting an error with no explanation: ...
0
votes
1answer
67 views

Configure initial directory

How can I configure the initial directory? By configure, I mean set it so that when Mathematica starts the initial directory is one of my choosing. By the by, what exactly is the significance of the ...

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