# All Questions

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 ...
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: ...
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 ...
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 ...
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 ...
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 ...
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. ...
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 ...
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 ...
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 ...
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) ...
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 ...
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: ...
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 ...
90 views

### How to solve this integral equation?

I am trying to solve for x the integral equation : ...
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?
55 views

### Manipulate executes twice [on hold]

I need help, guys! Here the script: ...
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 ...
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 ...
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 ...
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 ...
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 $3\times3$ ...
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 ...
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}. ...
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 ...
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 ...
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: ...
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 ...
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 ...
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 ...
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: ...
34 views

### Conjugate of InterpolatingFunction?

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

### Scan vs Map vs Apply

I cannot understand the difference between Apply, Scan, and Map. I have tried to play with ...
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 ...
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 ...
46 views

### Loading StatisticsLibrary

I need to use a number of functions from theStatisticsLibrary namespace. Since that is a bit of a mouthful I would like to import it, but I get errors: ...
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 ...
330 views

### singularity in NDSolve and Table command [on hold]

We are considering the following equations ...
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 ...
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 ...
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 ...
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 ...
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 ...
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, ...